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  200.   <section id="module-string">

  201. <span id="string-common-string-operations"></span><h1><a class="reference internal" href="#module-string" title="string: Common string operations."><code class="xref py py-mod docutils literal notranslate"><span class="pre">string</span></code></a> — Common string operations<a class="headerlink" href="#module-string" title="Link to this heading">¶</a></h1>

  202. <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.12/Lib/string.py">Lib/string.py</a></p>

  203. <hr class="docutils" />

  204. <div class="admonition seealso">

  205. <p class="admonition-title">See also</p>

  206. <p><a class="reference internal" href="stdtypes.html#textseq"><span class="std std-ref">Text Sequence Type — str</span></a></p>

  207. <p><a class="reference internal" href="stdtypes.html#string-methods"><span class="std std-ref">String Methods</span></a></p>

  208. </div>

  209. <section id="string-constants">

  210. <h2>String constants<a class="headerlink" href="#string-constants" title="Link to this heading">¶</a></h2>

  211. <p>The constants defined in this module are:</p>

  212. <dl class="py data">

  213. <dt class="sig sig-object py" id="string.ascii_letters">

  214. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">ascii_letters</span></span><a class="headerlink" href="#string.ascii_letters" title="Link to this definition">¶</a></dt>

  215. <dd><p>The concatenation of the <a class="reference internal" href="#string.ascii_lowercase" title="string.ascii_lowercase"><code class="xref py py-const docutils literal notranslate"><span class="pre">ascii_lowercase</span></code></a> and <a class="reference internal" href="#string.ascii_uppercase" title="string.ascii_uppercase"><code class="xref py py-const docutils literal notranslate"><span class="pre">ascii_uppercase</span></code></a>

  216. constants described below.  This value is not locale-dependent.</p>

  217. </dd></dl>

  218. 

  219. <dl class="py data">

  220. <dt class="sig sig-object py" id="string.ascii_lowercase">

  221. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">ascii_lowercase</span></span><a class="headerlink" href="#string.ascii_lowercase" title="Link to this definition">¶</a></dt>

  222. <dd><p>The lowercase letters <code class="docutils literal notranslate"><span class="pre">'abcdefghijklmnopqrstuvwxyz'</span></code>.  This value is not

  223. locale-dependent and will not change.</p>

  224. </dd></dl>

  225. 

  226. <dl class="py data">

  227. <dt class="sig sig-object py" id="string.ascii_uppercase">

  228. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">ascii_uppercase</span></span><a class="headerlink" href="#string.ascii_uppercase" title="Link to this definition">¶</a></dt>

  229. <dd><p>The uppercase letters <code class="docutils literal notranslate"><span class="pre">'ABCDEFGHIJKLMNOPQRSTUVWXYZ'</span></code>.  This value is not

  230. locale-dependent and will not change.</p>

  231. </dd></dl>

  232. 

  233. <dl class="py data">

  234. <dt class="sig sig-object py" id="string.digits">

  235. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">digits</span></span><a class="headerlink" href="#string.digits" title="Link to this definition">¶</a></dt>

  236. <dd><p>The string <code class="docutils literal notranslate"><span class="pre">'0123456789'</span></code>.</p>

  237. </dd></dl>

  238. 

  239. <dl class="py data">

  240. <dt class="sig sig-object py" id="string.hexdigits">

  241. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">hexdigits</span></span><a class="headerlink" href="#string.hexdigits" title="Link to this definition">¶</a></dt>

  242. <dd><p>The string <code class="docutils literal notranslate"><span class="pre">'0123456789abcdefABCDEF'</span></code>.</p>

  243. </dd></dl>

  244. 

  245. <dl class="py data">

  246. <dt class="sig sig-object py" id="string.octdigits">

  247. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">octdigits</span></span><a class="headerlink" href="#string.octdigits" title="Link to this definition">¶</a></dt>

  248. <dd><p>The string <code class="docutils literal notranslate"><span class="pre">'01234567'</span></code>.</p>

  249. </dd></dl>

  250. 

  251. <dl class="py data">

  252. <dt class="sig sig-object py" id="string.punctuation">

  253. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">punctuation</span></span><a class="headerlink" href="#string.punctuation" title="Link to this definition">¶</a></dt>

  254. <dd><p>String of ASCII characters which are considered punctuation characters

  255. in the <code class="docutils literal notranslate"><span class="pre">C</span></code> locale: <code class="docutils literal notranslate"><span class="pre">!&quot;#$%&amp;'()*+,-./:;&lt;=&gt;?&#64;[\]^_`{|}~</span></code>.</p>

  256. </dd></dl>

  257. 

  258. <dl class="py data">

  259. <dt class="sig sig-object py" id="string.printable">

  260. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">printable</span></span><a class="headerlink" href="#string.printable" title="Link to this definition">¶</a></dt>

  261. <dd><p>String of ASCII characters which are considered printable.  This is a

  262. combination of <a class="reference internal" href="#string.digits" title="string.digits"><code class="xref py py-const docutils literal notranslate"><span class="pre">digits</span></code></a>, <a class="reference internal" href="#string.ascii_letters" title="string.ascii_letters"><code class="xref py py-const docutils literal notranslate"><span class="pre">ascii_letters</span></code></a>, <a class="reference internal" href="#string.punctuation" title="string.punctuation"><code class="xref py py-const docutils literal notranslate"><span class="pre">punctuation</span></code></a>,

  263. and <a class="reference internal" href="#string.whitespace" title="string.whitespace"><code class="xref py py-const docutils literal notranslate"><span class="pre">whitespace</span></code></a>.</p>

  264. </dd></dl>

  265. 

  266. <dl class="py data">

  267. <dt class="sig sig-object py" id="string.whitespace">

  268. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">whitespace</span></span><a class="headerlink" href="#string.whitespace" title="Link to this definition">¶</a></dt>

  269. <dd><p>A string containing all ASCII characters that are considered whitespace.

  270. This includes the characters space, tab, linefeed, return, formfeed, and

  271. vertical tab.</p>

  272. </dd></dl>

  273. 

  274. </section>

  275. <section id="custom-string-formatting">

  276. <span id="string-formatting"></span><h2>Custom String Formatting<a class="headerlink" href="#custom-string-formatting" title="Link to this heading">¶</a></h2>

  277. <p>The built-in string class provides the ability to do complex variable

  278. substitutions and value formatting via the <a class="reference internal" href="stdtypes.html#str.format" title="str.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">format()</span></code></a> method described in

  279. <span class="target" id="index-0"></span><a class="pep reference external" href="https://peps.python.org/pep-3101/"><strong>PEP 3101</strong></a>.  The <a class="reference internal" href="#string.Formatter" title="string.Formatter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code></a> class in the <a class="reference internal" href="#module-string" title="string: Common string operations."><code class="xref py py-mod docutils literal notranslate"><span class="pre">string</span></code></a> module allows

  280. you to create and customize your own string formatting behaviors using the same

  281. implementation as the built-in <a class="reference internal" href="stdtypes.html#str.format" title="str.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">format()</span></code></a> method.</p>

  282. <dl class="py class">

  283. <dt class="sig sig-object py" id="string.Formatter">

  284. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">Formatter</span></span><a class="headerlink" href="#string.Formatter" title="Link to this definition">¶</a></dt>

  285. <dd><p>The <a class="reference internal" href="#string.Formatter" title="string.Formatter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code></a> class has the following public methods:</p>

  286. <dl class="py method">

  287. <dt class="sig sig-object py" id="string.Formatter.format">

  288. <span class="sig-name descname"><span class="pre">format</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">format_string</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">/</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span><span class="n"><span class="pre">args</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">**</span></span><span class="n"><span class="pre">kwargs</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.format" title="Link to this definition">¶</a></dt>

  289. <dd><p>The primary API method.  It takes a format string and

  290. an arbitrary set of positional and keyword arguments.

  291. It is just a wrapper that calls <a class="reference internal" href="#string.Formatter.vformat" title="string.Formatter.vformat"><code class="xref py py-meth docutils literal notranslate"><span class="pre">vformat()</span></code></a>.</p>

  292. <div class="versionchanged">

  293. <p><span class="versionmodified changed">Changed in version 3.7: </span>A format string argument is now <a class="reference internal" href="../glossary.html#positional-only-parameter"><span class="std std-ref">positional-only</span></a>.</p>

  294. </div>

  295. </dd></dl>

  296. 

  297. <dl class="py method">

  298. <dt class="sig sig-object py" id="string.Formatter.vformat">

  299. <span class="sig-name descname"><span class="pre">vformat</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">format_string</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">args</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">kwargs</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.vformat" title="Link to this definition">¶</a></dt>

  300. <dd><p>This function does the actual work of formatting.  It is exposed as a

  301. separate function for cases where you want to pass in a predefined

  302. dictionary of arguments, rather than unpacking and repacking the

  303. dictionary as individual arguments using the <code class="docutils literal notranslate"><span class="pre">*args</span></code> and <code class="docutils literal notranslate"><span class="pre">**kwargs</span></code>

  304. syntax.  <a class="reference internal" href="#string.Formatter.vformat" title="string.Formatter.vformat"><code class="xref py py-meth docutils literal notranslate"><span class="pre">vformat()</span></code></a> does the work of breaking up the format string

  305. into character data and replacement fields.  It calls the various

  306. methods described below.</p>

  307. </dd></dl>

  308. 

  309. <p>In addition, the <a class="reference internal" href="#string.Formatter" title="string.Formatter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code></a> defines a number of methods that are

  310. intended to be replaced by subclasses:</p>

  311. <dl class="py method">

  312. <dt class="sig sig-object py" id="string.Formatter.parse">

  313. <span class="sig-name descname"><span class="pre">parse</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">format_string</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.parse" title="Link to this definition">¶</a></dt>

  314. <dd><p>Loop over the format_string and return an iterable of tuples

  315. (<em>literal_text</em>, <em>field_name</em>, <em>format_spec</em>, <em>conversion</em>).  This is used

  316. by <a class="reference internal" href="#string.Formatter.vformat" title="string.Formatter.vformat"><code class="xref py py-meth docutils literal notranslate"><span class="pre">vformat()</span></code></a> to break the string into either literal text, or

  317. replacement fields.</p>

  318. <p>The values in the tuple conceptually represent a span of literal text

  319. followed by a single replacement field.  If there is no literal text

  320. (which can happen if two replacement fields occur consecutively), then

  321. <em>literal_text</em> will be a zero-length string.  If there is no replacement

  322. field, then the values of <em>field_name</em>, <em>format_spec</em> and <em>conversion</em>

  323. will be <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>

  324. </dd></dl>

  325. 

  326. <dl class="py method">

  327. <dt class="sig sig-object py" id="string.Formatter.get_field">

  328. <span class="sig-name descname"><span class="pre">get_field</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">field_name</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">args</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">kwargs</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.get_field" title="Link to this definition">¶</a></dt>

  329. <dd><p>Given <em>field_name</em> as returned by <a class="reference internal" href="#string.Formatter.parse" title="string.Formatter.parse"><code class="xref py py-meth docutils literal notranslate"><span class="pre">parse()</span></code></a> (see above), convert it to

  330. an object to be formatted.  Returns a tuple (obj, used_key).  The default

  331. version takes strings of the form defined in <span class="target" id="index-1"></span><a class="pep reference external" href="https://peps.python.org/pep-3101/"><strong>PEP 3101</strong></a>, such as

  332. “0[name]” or “label.title”.  <em>args</em> and <em>kwargs</em> are as passed in to

  333. <a class="reference internal" href="#string.Formatter.vformat" title="string.Formatter.vformat"><code class="xref py py-meth docutils literal notranslate"><span class="pre">vformat()</span></code></a>.  The return value <em>used_key</em> has the same meaning as the

  334. <em>key</em> parameter to <a class="reference internal" href="#string.Formatter.get_value" title="string.Formatter.get_value"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_value()</span></code></a>.</p>

  335. </dd></dl>

  336. 

  337. <dl class="py method">

  338. <dt class="sig sig-object py" id="string.Formatter.get_value">

  339. <span class="sig-name descname"><span class="pre">get_value</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">key</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">args</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">kwargs</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.get_value" title="Link to this definition">¶</a></dt>

  340. <dd><p>Retrieve a given field value.  The <em>key</em> argument will be either an

  341. integer or a string.  If it is an integer, it represents the index of the

  342. positional argument in <em>args</em>; if it is a string, then it represents a

  343. named argument in <em>kwargs</em>.</p>

  344. <p>The <em>args</em> parameter is set to the list of positional arguments to

  345. <a class="reference internal" href="#string.Formatter.vformat" title="string.Formatter.vformat"><code class="xref py py-meth docutils literal notranslate"><span class="pre">vformat()</span></code></a>, and the <em>kwargs</em> parameter is set to the dictionary of

  346. keyword arguments.</p>

  347. <p>For compound field names, these functions are only called for the first

  348. component of the field name; subsequent components are handled through

  349. normal attribute and indexing operations.</p>

  350. <p>So for example, the field expression ‘0.name’ would cause

  351. <a class="reference internal" href="#string.Formatter.get_value" title="string.Formatter.get_value"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_value()</span></code></a> to be called with a <em>key</em> argument of 0.  The <code class="docutils literal notranslate"><span class="pre">name</span></code>

  352. attribute will be looked up after <a class="reference internal" href="#string.Formatter.get_value" title="string.Formatter.get_value"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_value()</span></code></a> returns by calling the

  353. built-in <a class="reference internal" href="functions.html#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate"><span class="pre">getattr()</span></code></a> function.</p>

  354. <p>If the index or keyword refers to an item that does not exist, then an

  355. <a class="reference internal" href="exceptions.html#IndexError" title="IndexError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">IndexError</span></code></a> or <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> should be raised.</p>

  356. </dd></dl>

  357. 

  358. <dl class="py method">

  359. <dt class="sig sig-object py" id="string.Formatter.check_unused_args">

  360. <span class="sig-name descname"><span class="pre">check_unused_args</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">used_args</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">args</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">kwargs</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.check_unused_args" title="Link to this definition">¶</a></dt>

  361. <dd><p>Implement checking for unused arguments if desired.  The arguments to this

  362. function is the set of all argument keys that were actually referred to in

  363. the format string (integers for positional arguments, and strings for

  364. named arguments), and a reference to the <em>args</em> and <em>kwargs</em> that was

  365. passed to vformat.  The set of unused args can be calculated from these

  366. parameters.  <a class="reference internal" href="#string.Formatter.check_unused_args" title="string.Formatter.check_unused_args"><code class="xref py py-meth docutils literal notranslate"><span class="pre">check_unused_args()</span></code></a> is assumed to raise an exception if

  367. the check fails.</p>

  368. </dd></dl>

  369. 

  370. <dl class="py method">

  371. <dt class="sig sig-object py" id="string.Formatter.format_field">

  372. <span class="sig-name descname"><span class="pre">format_field</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">value</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">format_spec</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.format_field" title="Link to this definition">¶</a></dt>

  373. <dd><p><a class="reference internal" href="#string.Formatter.format_field" title="string.Formatter.format_field"><code class="xref py py-meth docutils literal notranslate"><span class="pre">format_field()</span></code></a> simply calls the global <a class="reference internal" href="functions.html#format" title="format"><code class="xref py py-func docutils literal notranslate"><span class="pre">format()</span></code></a> built-in.  The

  374. method is provided so that subclasses can override it.</p>

  375. </dd></dl>

  376. 

  377. <dl class="py method">

  378. <dt class="sig sig-object py" id="string.Formatter.convert_field">

  379. <span class="sig-name descname"><span class="pre">convert_field</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">value</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">conversion</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Formatter.convert_field" title="Link to this definition">¶</a></dt>

  380. <dd><p>Converts the value (returned by <a class="reference internal" href="#string.Formatter.get_field" title="string.Formatter.get_field"><code class="xref py py-meth docutils literal notranslate"><span class="pre">get_field()</span></code></a>) given a conversion type

  381. (as in the tuple returned by the <a class="reference internal" href="#string.Formatter.parse" title="string.Formatter.parse"><code class="xref py py-meth docutils literal notranslate"><span class="pre">parse()</span></code></a> method).  The default

  382. version understands ‘s’ (str), ‘r’ (repr) and ‘a’ (ascii) conversion

  383. types.</p>

  384. </dd></dl>

  385. 

  386. </dd></dl>

  387. 

  388. </section>

  389. <section id="format-string-syntax">

  390. <span id="formatstrings"></span><h2>Format String Syntax<a class="headerlink" href="#format-string-syntax" title="Link to this heading">¶</a></h2>

  391. <p>The <a class="reference internal" href="stdtypes.html#str.format" title="str.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.format()</span></code></a> method and the <a class="reference internal" href="#string.Formatter" title="string.Formatter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code></a> class share the same

  392. syntax for format strings (although in the case of <a class="reference internal" href="#string.Formatter" title="string.Formatter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code></a>,

  393. subclasses can define their own format string syntax).  The syntax is

  394. related to that of <a class="reference internal" href="../reference/lexical_analysis.html#f-strings"><span class="std std-ref">formatted string literals</span></a>, but it is

  395. less sophisticated and, in particular, does not support arbitrary expressions.</p>

  396. <p id="index-2">Format strings contain “replacement fields” surrounded by curly braces <code class="docutils literal notranslate"><span class="pre">{}</span></code>.

  397. Anything that is not contained in braces is considered literal text, which is

  398. copied unchanged to the output.  If you need to include a brace character in the

  399. literal text, it can be escaped by doubling: <code class="docutils literal notranslate"><span class="pre">{{</span></code> and <code class="docutils literal notranslate"><span class="pre">}}</span></code>.</p>

  400. <p>The grammar for a replacement field is as follows:</p>

  401. <pre>

  402. <strong id="grammar-token-format-string-replacement_field">replacement_field</strong> ::=  &quot;{&quot; [<a class="reference internal" href="#grammar-token-format-string-field_name"><code class="xref docutils literal notranslate"><span class="pre">field_name</span></code></a>] [&quot;!&quot; <a class="reference internal" href="#grammar-token-format-string-conversion"><code class="xref docutils literal notranslate"><span class="pre">conversion</span></code></a>] [&quot;:&quot; <a class="reference internal" href="#grammar-token-format-string-format_spec"><code class="xref docutils literal notranslate"><span class="pre">format_spec</span></code></a>] &quot;}&quot;

  403. <strong id="grammar-token-format-string-field_name">field_name       </strong> ::=  <a class="reference internal" href="#grammar-token-format-string-arg_name"><code class="xref docutils literal notranslate"><span class="pre">arg_name</span></code></a> (&quot;.&quot; <a class="reference internal" href="#grammar-token-format-string-attribute_name"><code class="xref docutils literal notranslate"><span class="pre">attribute_name</span></code></a> | &quot;[&quot; <a class="reference internal" href="#grammar-token-format-string-element_index"><code class="xref docutils literal notranslate"><span class="pre">element_index</span></code></a> &quot;]&quot;)*

  404. <strong id="grammar-token-format-string-arg_name">arg_name         </strong> ::=  [<a class="reference internal" href="../reference/lexical_analysis.html#grammar-token-python-grammar-identifier"><code class="xref docutils literal notranslate"><span class="pre">identifier</span></code></a> | <a class="reference internal" href="../reference/lexical_analysis.html#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a>+]

  405. <strong id="grammar-token-format-string-attribute_name">attribute_name   </strong> ::=  <a class="reference internal" href="../reference/lexical_analysis.html#grammar-token-python-grammar-identifier"><code class="xref docutils literal notranslate"><span class="pre">identifier</span></code></a>

  406. <strong id="grammar-token-format-string-element_index">element_index    </strong> ::=  <a class="reference internal" href="../reference/lexical_analysis.html#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a>+ | <a class="reference internal" href="#grammar-token-format-string-index_string"><code class="xref docutils literal notranslate"><span class="pre">index_string</span></code></a>

  407. <strong id="grammar-token-format-string-index_string">index_string     </strong> ::=  &lt;any source character except &quot;]&quot;&gt; +

  408. <strong id="grammar-token-format-string-conversion">conversion       </strong> ::=  &quot;r&quot; | &quot;s&quot; | &quot;a&quot;

  409. <strong id="grammar-token-format-string-format_spec">format_spec      </strong> ::=  <a class="reference internal" href="#grammar-token-format-spec-format_spec"><code class="xref docutils literal notranslate"><span class="pre">format-spec:format_spec</span></code></a>

  410. </pre>

  411. <p>In less formal terms, the replacement field can start with a <em>field_name</em> that specifies

  412. the object whose value is to be formatted and inserted

  413. into the output instead of the replacement field.

  414. The <em>field_name</em> is optionally followed by a  <em>conversion</em> field, which is

  415. preceded by an exclamation point <code class="docutils literal notranslate"><span class="pre">'!'</span></code>, and a <em>format_spec</em>, which is preceded

  416. by a colon <code class="docutils literal notranslate"><span class="pre">':'</span></code>.  These specify a non-default format for the replacement value.</p>

  417. <p>See also the <a class="reference internal" href="#formatspec"><span class="std std-ref">Format Specification Mini-Language</span></a> section.</p>

  418. <p>The <em>field_name</em> itself begins with an <em>arg_name</em> that is either a number or a

  419. keyword.  If it’s a number, it refers to a positional argument, and if it’s a keyword,

  420. it refers to a named keyword argument. An <em>arg_name</em> is treated as a number if

  421. a call to <a class="reference internal" href="stdtypes.html#str.isdecimal" title="str.isdecimal"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.isdecimal()</span></code></a> on the string would return true.

  422. If the numerical arg_names in a format string

  423. are 0, 1, 2, … in sequence, they can all be omitted (not just some)

  424. and the numbers 0, 1, 2, … will be automatically inserted in that order.

  425. Because <em>arg_name</em> is not quote-delimited, it is not possible to specify arbitrary

  426. dictionary keys (e.g., the strings <code class="docutils literal notranslate"><span class="pre">'10'</span></code> or <code class="docutils literal notranslate"><span class="pre">':-]'</span></code>) within a format string.

  427. The <em>arg_name</em> can be followed by any number of index or

  428. attribute expressions. An expression of the form <code class="docutils literal notranslate"><span class="pre">'.name'</span></code> selects the named

  429. attribute using <a class="reference internal" href="functions.html#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate"><span class="pre">getattr()</span></code></a>, while an expression of the form <code class="docutils literal notranslate"><span class="pre">'[index]'</span></code>

  430. does an index lookup using <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__getitem__()</span></code></a>.</p>

  431. <div class="versionchanged">

  432. <p><span class="versionmodified changed">Changed in version 3.1: </span>The positional argument specifiers can be omitted for <a class="reference internal" href="stdtypes.html#str.format" title="str.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.format()</span></code></a>,

  433. so <code class="docutils literal notranslate"><span class="pre">'{}</span> <span class="pre">{}'.format(a,</span> <span class="pre">b)</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">'{0}</span> <span class="pre">{1}'.format(a,</span> <span class="pre">b)</span></code>.</p>

  434. </div>

  435. <div class="versionchanged">

  436. <p><span class="versionmodified changed">Changed in version 3.4: </span>The positional argument specifiers can be omitted for <a class="reference internal" href="#string.Formatter" title="string.Formatter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code></a>.</p>

  437. </div>

  438. <p>Some simple format string examples:</p>

  439. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="s2">&quot;First, thou shalt count to </span><span class="si">{0}</span><span class="s2">&quot;</span>  <span class="c1"># References first positional argument</span>

  440. <span class="s2">&quot;Bring me a </span><span class="si">{}</span><span class="s2">&quot;</span>                   <span class="c1"># Implicitly references the first positional argument</span>

  441. <span class="s2">&quot;From </span><span class="si">{}</span><span class="s2"> to </span><span class="si">{}</span><span class="s2">&quot;</span>                   <span class="c1"># Same as &quot;From {0} to {1}&quot;</span>

  442. <span class="s2">&quot;My quest is </span><span class="si">{name}</span><span class="s2">&quot;</span>              <span class="c1"># References keyword argument &#39;name&#39;</span>

  443. <span class="s2">&quot;Weight in tons </span><span class="si">{0.weight}</span><span class="s2">&quot;</span>       <span class="c1"># &#39;weight&#39; attribute of first positional arg</span>

  444. <span class="s2">&quot;Units destroyed: </span><span class="si">{players[0]}</span><span class="s2">&quot;</span>   <span class="c1"># First element of keyword argument &#39;players&#39;.</span>

  445. </pre></div>

  446. </div>

  447. <p>The <em>conversion</em> field causes a type coercion before formatting.  Normally, the

  448. job of formatting a value is done by the <a class="reference internal" href="../reference/datamodel.html#object.__format__" title="object.__format__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__format__()</span></code></a> method of the value

  449. itself.  However, in some cases it is desirable to force a type to be formatted

  450. as a string, overriding its own definition of formatting.  By converting the

  451. value to a string before calling <a class="reference internal" href="../reference/datamodel.html#object.__format__" title="object.__format__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__format__()</span></code></a>, the normal formatting logic

  452. is bypassed.</p>

  453. <p>Three conversion flags are currently supported: <code class="docutils literal notranslate"><span class="pre">'!s'</span></code> which calls <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate"><span class="pre">str()</span></code></a>

  454. on the value, <code class="docutils literal notranslate"><span class="pre">'!r'</span></code> which calls <a class="reference internal" href="functions.html#repr" title="repr"><code class="xref py py-func docutils literal notranslate"><span class="pre">repr()</span></code></a> and <code class="docutils literal notranslate"><span class="pre">'!a'</span></code> which calls

  455. <a class="reference internal" href="functions.html#ascii" title="ascii"><code class="xref py py-func docutils literal notranslate"><span class="pre">ascii()</span></code></a>.</p>

  456. <p>Some examples:</p>

  457. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="s2">&quot;Harold&#39;s a clever </span><span class="si">{0!s}</span><span class="s2">&quot;</span>        <span class="c1"># Calls str() on the argument first</span>

  458. <span class="s2">&quot;Bring out the holy </span><span class="si">{name!r}</span><span class="s2">&quot;</span>    <span class="c1"># Calls repr() on the argument first</span>

  459. <span class="s2">&quot;More </span><span class="si">{!a}</span><span class="s2">&quot;</span>                      <span class="c1"># Calls ascii() on the argument first</span>

  460. </pre></div>

  461. </div>

  462. <p>The <em>format_spec</em> field contains a specification of how the value should be

  463. presented, including such details as field width, alignment, padding, decimal

  464. precision and so on.  Each value type can define its own “formatting

  465. mini-language” or interpretation of the <em>format_spec</em>.</p>

  466. <p>Most built-in types support a common formatting mini-language, which is

  467. described in the next section.</p>

  468. <p>A <em>format_spec</em> field can also include nested replacement fields within it.

  469. These nested replacement fields may contain a field name, conversion flag

  470. and format specification, but deeper nesting is

  471. not allowed.  The replacement fields within the

  472. format_spec are substituted before the <em>format_spec</em> string is interpreted.

  473. This allows the formatting of a value to be dynamically specified.</p>

  474. <p>See the <a class="reference internal" href="#formatexamples"><span class="std std-ref">Format examples</span></a> section for some examples.</p>

  475. <section id="format-specification-mini-language">

  476. <span id="formatspec"></span><h3>Format Specification Mini-Language<a class="headerlink" href="#format-specification-mini-language" title="Link to this heading">¶</a></h3>

  477. <p>“Format specifications” are used within replacement fields contained within a

  478. format string to define how individual values are presented (see

  479. <a class="reference internal" href="#formatstrings"><span class="std std-ref">Format String Syntax</span></a> and <a class="reference internal" href="../reference/lexical_analysis.html#f-strings"><span class="std std-ref">f-strings</span></a>).

  480. They can also be passed directly to the built-in

  481. <a class="reference internal" href="functions.html#format" title="format"><code class="xref py py-func docutils literal notranslate"><span class="pre">format()</span></code></a> function.  Each formattable type may define how the format

  482. specification is to be interpreted.</p>

  483. <p>Most built-in types implement the following options for format specifications,

  484. although some of the formatting options are only supported by the numeric types.</p>

  485. <p>A general convention is that an empty format specification produces

  486. the same result as if you had called <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate"><span class="pre">str()</span></code></a> on the value. A

  487. non-empty format specification typically modifies the result.</p>

  488. <p>The general form of a <em>standard format specifier</em> is:</p>

  489. <pre>

  490. <strong id="grammar-token-format-spec-format_spec">format_spec    </strong> ::=  [[<a class="reference internal" href="#grammar-token-format-spec-fill"><code class="xref docutils literal notranslate"><span class="pre">fill</span></code></a>]<a class="reference internal" href="#grammar-token-format-spec-align"><code class="xref docutils literal notranslate"><span class="pre">align</span></code></a>][<a class="reference internal" href="#grammar-token-format-spec-sign"><code class="xref docutils literal notranslate"><span class="pre">sign</span></code></a>][&quot;z&quot;][&quot;#&quot;][&quot;0&quot;][<a class="reference internal" href="#grammar-token-format-spec-width"><code class="xref docutils literal notranslate"><span class="pre">width</span></code></a>][<a class="reference internal" href="#grammar-token-format-spec-grouping_option"><code class="xref docutils literal notranslate"><span class="pre">grouping_option</span></code></a>][&quot;.&quot; <a class="reference internal" href="#grammar-token-format-spec-precision"><code class="xref docutils literal notranslate"><span class="pre">precision</span></code></a>][<a class="reference internal" href="#grammar-token-format-spec-type"><code class="xref docutils literal notranslate"><span class="pre">type</span></code></a>]

  491. <strong id="grammar-token-format-spec-fill">fill           </strong> ::=  &lt;any character&gt;

  492. <strong id="grammar-token-format-spec-align">align          </strong> ::=  &quot;&lt;&quot; | &quot;&gt;&quot; | &quot;=&quot; | &quot;^&quot;

  493. <strong id="grammar-token-format-spec-sign">sign           </strong> ::=  &quot;+&quot; | &quot;-&quot; | &quot; &quot;

  494. <strong id="grammar-token-format-spec-width">width          </strong> ::=  <a class="reference internal" href="../reference/lexical_analysis.html#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a>+

  495. <strong id="grammar-token-format-spec-grouping_option">grouping_option</strong> ::=  &quot;_&quot; | &quot;,&quot;

  496. <strong id="grammar-token-format-spec-precision">precision      </strong> ::=  <a class="reference internal" href="../reference/lexical_analysis.html#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a>+

  497. <strong id="grammar-token-format-spec-type">type           </strong> ::=  &quot;b&quot; | &quot;c&quot; | &quot;d&quot; | &quot;e&quot; | &quot;E&quot; | &quot;f&quot; | &quot;F&quot; | &quot;g&quot; | &quot;G&quot; | &quot;n&quot; | &quot;o&quot; | &quot;s&quot; | &quot;x&quot; | &quot;X&quot; | &quot;%&quot;

  498. </pre>

  499. <p>If a valid <em>align</em> value is specified, it can be preceded by a <em>fill</em>

  500. character that can be any character and defaults to a space if omitted.

  501. It is not possible to use a literal curly brace (”<code class="docutils literal notranslate"><span class="pre">{</span></code>” or “<code class="docutils literal notranslate"><span class="pre">}</span></code>”) as

  502. the <em>fill</em> character in a <a class="reference internal" href="../reference/lexical_analysis.html#f-strings"><span class="std std-ref">formatted string literal</span></a> or when using the <a class="reference internal" href="stdtypes.html#str.format" title="str.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.format()</span></code></a>

  503. method.  However, it is possible to insert a curly brace

  504. with a nested replacement field.  This limitation doesn’t

  505. affect the <a class="reference internal" href="functions.html#format" title="format"><code class="xref py py-func docutils literal notranslate"><span class="pre">format()</span></code></a> function.</p>

  506. <p>The meaning of the various alignment options is as follows:</p>

  507. <table class="docutils align-default" id="index-3">

  508. <thead>

  509. <tr class="row-odd"><th class="head"><p>Option</p></th>

  510. <th class="head"><p>Meaning</p></th>

  511. </tr>

  512. </thead>

  513. <tbody>

  514. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'&lt;'</span></code></p></td>

  515. <td><p>Forces the field to be left-aligned within the available

  516. space (this is the default for most objects).</p></td>

  517. </tr>

  518. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'&gt;'</span></code></p></td>

  519. <td><p>Forces the field to be right-aligned within the

  520. available space (this is the default for numbers).</p></td>

  521. </tr>

  522. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'='</span></code></p></td>

  523. <td><p>Forces the padding to be placed after the sign (if any)

  524. but before the digits.  This is used for printing fields

  525. in the form ‘+000000120’. This alignment option is only

  526. valid for numeric types.  It becomes the default for

  527. numbers when ‘0’ immediately precedes the field width.</p></td>

  528. </tr>

  529. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'^'</span></code></p></td>

  530. <td><p>Forces the field to be centered within the available

  531. space.</p></td>

  532. </tr>

  533. </tbody>

  534. </table>

  535. <p>Note that unless a minimum field width is defined, the field width will always

  536. be the same size as the data to fill it, so that the alignment option has no

  537. meaning in this case.</p>

  538. <p>The <em>sign</em> option is only valid for number types, and can be one of the

  539. following:</p>

  540. <table class="docutils align-default" id="index-4">

  541. <thead>

  542. <tr class="row-odd"><th class="head"><p>Option</p></th>

  543. <th class="head"><p>Meaning</p></th>

  544. </tr>

  545. </thead>

  546. <tbody>

  547. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'+'</span></code></p></td>

  548. <td><p>indicates that a sign should be used for both

  549. positive as well as negative numbers.</p></td>

  550. </tr>

  551. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'-'</span></code></p></td>

  552. <td><p>indicates that a sign should be used only for negative

  553. numbers (this is the default behavior).</p></td>

  554. </tr>

  555. <tr class="row-even"><td><p>space</p></td>

  556. <td><p>indicates that a leading space should be used on

  557. positive numbers, and a minus sign on negative numbers.</p></td>

  558. </tr>

  559. </tbody>

  560. </table>

  561. <p id="index-5">The <code class="docutils literal notranslate"><span class="pre">'z'</span></code> option coerces negative zero floating-point values to positive

  562. zero after rounding to the format precision.  This option is only valid for

  563. floating-point presentation types.</p>

  564. <div class="versionchanged">

  565. <p><span class="versionmodified changed">Changed in version 3.11: </span>Added the <code class="docutils literal notranslate"><span class="pre">'z'</span></code> option (see also <span class="target" id="index-6"></span><a class="pep reference external" href="https://peps.python.org/pep-0682/"><strong>PEP 682</strong></a>).</p>

  566. </div>

  567. <p id="index-7">The <code class="docutils literal notranslate"><span class="pre">'#'</span></code> option causes the “alternate form” to be used for the

  568. conversion.  The alternate form is defined differently for different

  569. types.  This option is only valid for integer, float and complex

  570. types. For integers, when binary, octal, or hexadecimal output

  571. is used, this option adds the respective prefix <code class="docutils literal notranslate"><span class="pre">'0b'</span></code>, <code class="docutils literal notranslate"><span class="pre">'0o'</span></code>,

  572. <code class="docutils literal notranslate"><span class="pre">'0x'</span></code>, or <code class="docutils literal notranslate"><span class="pre">'0X'</span></code> to the output value. For float and complex the

  573. alternate form causes the result of the conversion to always contain a

  574. decimal-point character, even if no digits follow it. Normally, a

  575. decimal-point character appears in the result of these conversions

  576. only if a digit follows it. In addition, for <code class="docutils literal notranslate"><span class="pre">'g'</span></code> and <code class="docutils literal notranslate"><span class="pre">'G'</span></code>

  577. conversions, trailing zeros are not removed from the result.</p>

  578. <p id="index-8">The <code class="docutils literal notranslate"><span class="pre">','</span></code> option signals the use of a comma for a thousands separator.

  579. For a locale aware separator, use the <code class="docutils literal notranslate"><span class="pre">'n'</span></code> integer presentation type

  580. instead.</p>

  581. <div class="versionchanged">

  582. <p><span class="versionmodified changed">Changed in version 3.1: </span>Added the <code class="docutils literal notranslate"><span class="pre">','</span></code> option (see also <span class="target" id="index-9"></span><a class="pep reference external" href="https://peps.python.org/pep-0378/"><strong>PEP 378</strong></a>).</p>

  583. </div>

  584. <p id="index-10">The <code class="docutils literal notranslate"><span class="pre">'_'</span></code> option signals the use of an underscore for a thousands

  585. separator for floating point presentation types and for integer

  586. presentation type <code class="docutils literal notranslate"><span class="pre">'d'</span></code>.  For integer presentation types <code class="docutils literal notranslate"><span class="pre">'b'</span></code>,

  587. <code class="docutils literal notranslate"><span class="pre">'o'</span></code>, <code class="docutils literal notranslate"><span class="pre">'x'</span></code>, and <code class="docutils literal notranslate"><span class="pre">'X'</span></code>, underscores will be inserted every 4

  588. digits.  For other presentation types, specifying this option is an

  589. error.</p>

  590. <div class="versionchanged">

  591. <p><span class="versionmodified changed">Changed in version 3.6: </span>Added the <code class="docutils literal notranslate"><span class="pre">'_'</span></code> option (see also <span class="target" id="index-11"></span><a class="pep reference external" href="https://peps.python.org/pep-0515/"><strong>PEP 515</strong></a>).</p>

  592. </div>

  593. <p><em>width</em> is a decimal integer defining the minimum total field width,

  594. including any prefixes, separators, and other formatting characters.

  595. If not specified, then the field width will be determined by the content.</p>

  596. <p>When no explicit alignment is given, preceding the <em>width</em> field by a zero

  597. (<code class="docutils literal notranslate"><span class="pre">'0'</span></code>) character enables

  598. sign-aware zero-padding for numeric types.  This is equivalent to a <em>fill</em>

  599. character of <code class="docutils literal notranslate"><span class="pre">'0'</span></code> with an <em>alignment</em> type of <code class="docutils literal notranslate"><span class="pre">'='</span></code>.</p>

  600. <div class="versionchanged">

  601. <p><span class="versionmodified changed">Changed in version 3.10: </span>Preceding the <em>width</em> field by <code class="docutils literal notranslate"><span class="pre">'0'</span></code> no longer affects the default

  602. alignment for strings.</p>

  603. </div>

  604. <p>The <em>precision</em> is a decimal integer indicating how many digits should be

  605. displayed after the decimal point for presentation types

  606. <code class="docutils literal notranslate"><span class="pre">'f'</span></code> and <code class="docutils literal notranslate"><span class="pre">'F'</span></code>, or before and after the decimal point for presentation

  607. types <code class="docutils literal notranslate"><span class="pre">'g'</span></code> or <code class="docutils literal notranslate"><span class="pre">'G'</span></code>.  For string presentation types the field

  608. indicates the maximum field size - in other words, how many characters will be

  609. used from the field content.  The <em>precision</em> is not allowed for integer

  610. presentation types.</p>

  611. <p>Finally, the <em>type</em> determines how the data should be presented.</p>

  612. <p>The available string presentation types are:</p>

  613. <blockquote>

  614. <div><table class="docutils align-default">

  615. <thead>

  616. <tr class="row-odd"><th class="head"><p>Type</p></th>

  617. <th class="head"><p>Meaning</p></th>

  618. </tr>

  619. </thead>

  620. <tbody>

  621. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'s'</span></code></p></td>

  622. <td><p>String format. This is the default type for strings and

  623. may be omitted.</p></td>

  624. </tr>

  625. <tr class="row-odd"><td><p>None</p></td>

  626. <td><p>The same as <code class="docutils literal notranslate"><span class="pre">'s'</span></code>.</p></td>

  627. </tr>

  628. </tbody>

  629. </table>

  630. </div></blockquote>

  631. <p>The available integer presentation types are:</p>

  632. <blockquote>

  633. <div><table class="docutils align-default">

  634. <thead>

  635. <tr class="row-odd"><th class="head"><p>Type</p></th>

  636. <th class="head"><p>Meaning</p></th>

  637. </tr>

  638. </thead>

  639. <tbody>

  640. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'b'</span></code></p></td>

  641. <td><p>Binary format. Outputs the number in base 2.</p></td>

  642. </tr>

  643. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'c'</span></code></p></td>

  644. <td><p>Character. Converts the integer to the corresponding

  645. unicode character before printing.</p></td>

  646. </tr>

  647. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'d'</span></code></p></td>

  648. <td><p>Decimal Integer. Outputs the number in base 10.</p></td>

  649. </tr>

  650. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'o'</span></code></p></td>

  651. <td><p>Octal format. Outputs the number in base 8.</p></td>

  652. </tr>

  653. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'x'</span></code></p></td>

  654. <td><p>Hex format. Outputs the number in base 16, using

  655. lower-case letters for the digits above 9.</p></td>

  656. </tr>

  657. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'X'</span></code></p></td>

  658. <td><p>Hex format. Outputs the number in base 16, using

  659. upper-case letters for the digits above 9.

  660. In case <code class="docutils literal notranslate"><span class="pre">'#'</span></code> is specified, the prefix <code class="docutils literal notranslate"><span class="pre">'0x'</span></code> will

  661. be upper-cased to <code class="docutils literal notranslate"><span class="pre">'0X'</span></code> as well.</p></td>

  662. </tr>

  663. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'n'</span></code></p></td>

  664. <td><p>Number. This is the same as <code class="docutils literal notranslate"><span class="pre">'d'</span></code>, except that it uses

  665. the current locale setting to insert the appropriate

  666. number separator characters.</p></td>

  667. </tr>

  668. <tr class="row-odd"><td><p>None</p></td>

  669. <td><p>The same as <code class="docutils literal notranslate"><span class="pre">'d'</span></code>.</p></td>

  670. </tr>

  671. </tbody>

  672. </table>

  673. </div></blockquote>

  674. <p>In addition to the above presentation types, integers can be formatted

  675. with the floating point presentation types listed below (except

  676. <code class="docutils literal notranslate"><span class="pre">'n'</span></code> and <code class="docutils literal notranslate"><span class="pre">None</span></code>). When doing so, <a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-func docutils literal notranslate"><span class="pre">float()</span></code></a> is used to convert the

  677. integer to a floating point number before formatting.</p>

  678. <p>The available presentation types for <a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a> and

  679. <a class="reference internal" href="decimal.html#decimal.Decimal" title="decimal.Decimal"><code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code></a> values are:</p>

  680. <blockquote>

  681. <div><table class="docutils align-default">

  682. <thead>

  683. <tr class="row-odd"><th class="head"><p>Type</p></th>

  684. <th class="head"><p>Meaning</p></th>

  685. </tr>

  686. </thead>

  687. <tbody>

  688. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'e'</span></code></p></td>

  689. <td><p>Scientific notation. For a given precision <code class="docutils literal notranslate"><span class="pre">p</span></code>,

  690. formats the number in scientific notation with the

  691. letter ‘e’ separating the coefficient from the exponent.

  692. The coefficient has one digit before and <code class="docutils literal notranslate"><span class="pre">p</span></code> digits

  693. after the decimal point, for a total of <code class="docutils literal notranslate"><span class="pre">p</span> <span class="pre">+</span> <span class="pre">1</span></code>

  694. significant digits. With no precision given, uses a

  695. precision of <code class="docutils literal notranslate"><span class="pre">6</span></code> digits after the decimal point for

  696. <a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a>, and shows all coefficient digits

  697. for <a class="reference internal" href="decimal.html#decimal.Decimal" title="decimal.Decimal"><code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code></a>. If no digits follow the

  698. decimal point, the decimal point is also removed unless

  699. the <code class="docutils literal notranslate"><span class="pre">#</span></code> option is used.</p></td>

  700. </tr>

  701. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'E'</span></code></p></td>

  702. <td><p>Scientific notation. Same as <code class="docutils literal notranslate"><span class="pre">'e'</span></code> except it uses

  703. an upper case ‘E’ as the separator character.</p></td>

  704. </tr>

  705. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'f'</span></code></p></td>

  706. <td><p>Fixed-point notation. For a given precision <code class="docutils literal notranslate"><span class="pre">p</span></code>,

  707. formats the number as a decimal number with exactly

  708. <code class="docutils literal notranslate"><span class="pre">p</span></code> digits following the decimal point. With no

  709. precision given, uses a precision of <code class="docutils literal notranslate"><span class="pre">6</span></code> digits after

  710. the decimal point for <a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a>, and uses a

  711. precision large enough to show all coefficient digits

  712. for <a class="reference internal" href="decimal.html#decimal.Decimal" title="decimal.Decimal"><code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code></a>. If no digits follow the

  713. decimal point, the decimal point is also removed unless

  714. the <code class="docutils literal notranslate"><span class="pre">#</span></code> option is used.</p></td>

  715. </tr>

  716. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'F'</span></code></p></td>

  717. <td><p>Fixed-point notation. Same as <code class="docutils literal notranslate"><span class="pre">'f'</span></code>, but converts

  718. <code class="docutils literal notranslate"><span class="pre">nan</span></code> to  <code class="docutils literal notranslate"><span class="pre">NAN</span></code> and <code class="docutils literal notranslate"><span class="pre">inf</span></code> to <code class="docutils literal notranslate"><span class="pre">INF</span></code>.</p></td>

  719. </tr>

  720. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'g'</span></code></p></td>

  721. <td><p>General format.  For a given precision <code class="docutils literal notranslate"><span class="pre">p</span> <span class="pre">&gt;=</span> <span class="pre">1</span></code>,

  722. this rounds the number to <code class="docutils literal notranslate"><span class="pre">p</span></code> significant digits and

  723. then formats the result in either fixed-point format

  724. or in scientific notation, depending on its magnitude.

  725. A precision of <code class="docutils literal notranslate"><span class="pre">0</span></code> is treated as equivalent to a

  726. precision of <code class="docutils literal notranslate"><span class="pre">1</span></code>.</p>

  727. <p>The precise rules are as follows: suppose that the

  728. result formatted with presentation type <code class="docutils literal notranslate"><span class="pre">'e'</span></code> and

  729. precision <code class="docutils literal notranslate"><span class="pre">p-1</span></code> would have exponent <code class="docutils literal notranslate"><span class="pre">exp</span></code>.  Then,

  730. if <code class="docutils literal notranslate"><span class="pre">m</span> <span class="pre">&lt;=</span> <span class="pre">exp</span> <span class="pre">&lt;</span> <span class="pre">p</span></code>, where <code class="docutils literal notranslate"><span class="pre">m</span></code> is -4 for floats and -6

  731. for <a class="reference internal" href="decimal.html#decimal.Decimal" title="decimal.Decimal"><code class="xref py py-class docutils literal notranslate"><span class="pre">Decimals</span></code></a>, the number is

  732. formatted with presentation type <code class="docutils literal notranslate"><span class="pre">'f'</span></code> and precision

  733. <code class="docutils literal notranslate"><span class="pre">p-1-exp</span></code>.  Otherwise, the number is formatted

  734. with presentation type <code class="docutils literal notranslate"><span class="pre">'e'</span></code> and precision <code class="docutils literal notranslate"><span class="pre">p-1</span></code>.

  735. In both cases insignificant trailing zeros are removed

  736. from the significand, and the decimal point is also

  737. removed if there are no remaining digits following it,

  738. unless the <code class="docutils literal notranslate"><span class="pre">'#'</span></code> option is used.</p>

  739. <p>With no precision given, uses a precision of <code class="docutils literal notranslate"><span class="pre">6</span></code>

  740. significant digits for <a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a>. For

  741. <a class="reference internal" href="decimal.html#decimal.Decimal" title="decimal.Decimal"><code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code></a>, the coefficient of the result

  742. is formed from the coefficient digits of the value;

  743. scientific notation is used for values smaller than

  744. <code class="docutils literal notranslate"><span class="pre">1e-6</span></code> in absolute value and values where the place

  745. value of the least significant digit is larger than 1,

  746. and fixed-point notation is used otherwise.</p>

  747. <p>Positive and negative infinity, positive and negative

  748. zero, and nans, are formatted as <code class="docutils literal notranslate"><span class="pre">inf</span></code>, <code class="docutils literal notranslate"><span class="pre">-inf</span></code>,

  749. <code class="docutils literal notranslate"><span class="pre">0</span></code>, <code class="docutils literal notranslate"><span class="pre">-0</span></code> and <code class="docutils literal notranslate"><span class="pre">nan</span></code> respectively, regardless of

  750. the precision.</p>

  751. </td>

  752. </tr>

  753. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'G'</span></code></p></td>

  754. <td><p>General format. Same as <code class="docutils literal notranslate"><span class="pre">'g'</span></code> except switches to

  755. <code class="docutils literal notranslate"><span class="pre">'E'</span></code> if the number gets too large. The

  756. representations of infinity and NaN are uppercased, too.</p></td>

  757. </tr>

  758. <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'n'</span></code></p></td>

  759. <td><p>Number. This is the same as <code class="docutils literal notranslate"><span class="pre">'g'</span></code>, except that it uses

  760. the current locale setting to insert the appropriate

  761. number separator characters.</p></td>

  762. </tr>

  763. <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'%'</span></code></p></td>

  764. <td><p>Percentage. Multiplies the number by 100 and displays

  765. in fixed (<code class="docutils literal notranslate"><span class="pre">'f'</span></code>) format, followed by a percent sign.</p></td>

  766. </tr>

  767. <tr class="row-even"><td><p>None</p></td>

  768. <td><p>For <a class="reference internal" href="functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a> this is the same as <code class="docutils literal notranslate"><span class="pre">'g'</span></code>, except

  769. that when fixed-point notation is used to format the

  770. result, it always includes at least one digit past the

  771. decimal point. The precision used is as large as needed

  772. to represent the given value faithfully.</p>

  773. <p>For <a class="reference internal" href="decimal.html#decimal.Decimal" title="decimal.Decimal"><code class="xref py py-class docutils literal notranslate"><span class="pre">Decimal</span></code></a>, this is the same as

  774. either <code class="docutils literal notranslate"><span class="pre">'g'</span></code> or <code class="docutils literal notranslate"><span class="pre">'G'</span></code> depending on the value of

  775. <code class="docutils literal notranslate"><span class="pre">context.capitals</span></code> for the current decimal context.</p>

  776. <p>The overall effect is to match the output of <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate"><span class="pre">str()</span></code></a>

  777. as altered by the other format modifiers.</p>

  778. </td>

  779. </tr>

  780. </tbody>

  781. </table>

  782. </div></blockquote>

  783. </section>

  784. <section id="format-examples">

  785. <span id="formatexamples"></span><h3>Format examples<a class="headerlink" href="#format-examples" title="Link to this heading">¶</a></h3>

  786. <p>This section contains examples of the <a class="reference internal" href="stdtypes.html#str.format" title="str.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.format()</span></code></a> syntax and

  787. comparison with the old <code class="docutils literal notranslate"><span class="pre">%</span></code>-formatting.</p>

  788. <p>In most of the cases the syntax is similar to the old <code class="docutils literal notranslate"><span class="pre">%</span></code>-formatting, with the

  789. addition of the <code class="docutils literal notranslate"><span class="pre">{}</span></code> and with <code class="docutils literal notranslate"><span class="pre">:</span></code> used instead of <code class="docutils literal notranslate"><span class="pre">%</span></code>.

  790. For example, <code class="docutils literal notranslate"><span class="pre">'%03.2f'</span></code> can be translated to <code class="docutils literal notranslate"><span class="pre">'{:03.2f}'</span></code>.</p>

  791. <p>The new format syntax also supports new and different options, shown in the

  792. following examples.</p>

  793. <p>Accessing arguments by position:</p>

  794. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{0}</span><span class="s1">, </span><span class="si">{1}</span><span class="s1">, </span><span class="si">{2}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">)</span>

  795. <span class="go">&#39;a, b, c&#39;</span>

  796. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{}</span><span class="s1">, </span><span class="si">{}</span><span class="s1">, </span><span class="si">{}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">)</span>  <span class="c1"># 3.1+ only</span>

  797. <span class="go">&#39;a, b, c&#39;</span>

  798. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{2}</span><span class="s1">, </span><span class="si">{1}</span><span class="s1">, </span><span class="si">{0}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;a&#39;</span><span class="p">,</span> <span class="s1">&#39;b&#39;</span><span class="p">,</span> <span class="s1">&#39;c&#39;</span><span class="p">)</span>

  799. <span class="go">&#39;c, b, a&#39;</span>

  800. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{2}</span><span class="s1">, </span><span class="si">{1}</span><span class="s1">, </span><span class="si">{0}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="o">*</span><span class="s1">&#39;abc&#39;</span><span class="p">)</span>      <span class="c1"># unpacking argument sequence</span>

  801. <span class="go">&#39;c, b, a&#39;</span>

  802. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{0}{1}{0}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;abra&#39;</span><span class="p">,</span> <span class="s1">&#39;cad&#39;</span><span class="p">)</span>   <span class="c1"># arguments&#39; indices can be repeated</span>

  803. <span class="go">&#39;abracadabra&#39;</span>

  804. </pre></div>

  805. </div>

  806. <p>Accessing arguments by name:</p>

  807. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;Coordinates: </span><span class="si">{latitude}</span><span class="s1">, </span><span class="si">{longitude}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">latitude</span><span class="o">=</span><span class="s1">&#39;37.24N&#39;</span><span class="p">,</span> <span class="n">longitude</span><span class="o">=</span><span class="s1">&#39;-115.81W&#39;</span><span class="p">)</span>

  808. <span class="go">&#39;Coordinates: 37.24N, -115.81W&#39;</span>

  809. <span class="gp">&gt;&gt;&gt; </span><span class="n">coord</span> <span class="o">=</span> <span class="p">{</span><span class="s1">&#39;latitude&#39;</span><span class="p">:</span> <span class="s1">&#39;37.24N&#39;</span><span class="p">,</span> <span class="s1">&#39;longitude&#39;</span><span class="p">:</span> <span class="s1">&#39;-115.81W&#39;</span><span class="p">}</span>

  810. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;Coordinates: </span><span class="si">{latitude}</span><span class="s1">, </span><span class="si">{longitude}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="o">**</span><span class="n">coord</span><span class="p">)</span>

  811. <span class="go">&#39;Coordinates: 37.24N, -115.81W&#39;</span>

  812. </pre></div>

  813. </div>

  814. <p>Accessing arguments’ attributes:</p>

  815. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">c</span> <span class="o">=</span> <span class="mi">3</span><span class="o">-</span><span class="mi">5</span><span class="n">j</span>

  816. <span class="gp">&gt;&gt;&gt; </span><span class="p">(</span><span class="s1">&#39;The complex number </span><span class="si">{0}</span><span class="s1"> is formed from the real part </span><span class="si">{0.real}</span><span class="s1"> &#39;</span>

  817. <span class="gp">... </span> <span class="s1">&#39;and the imaginary part </span><span class="si">{0.imag}</span><span class="s1">.&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">c</span><span class="p">)</span>

  818. <span class="go">&#39;The complex number (3-5j) is formed from the real part 3.0 and the imaginary part -5.0.&#39;</span>

  819. <span class="gp">&gt;&gt;&gt; </span><span class="k">class</span> <span class="nc">Point</span><span class="p">:</span>

  820. <span class="gp">... </span>    <span class="k">def</span> <span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">):</span>

  821. <span class="gp">... </span>        <span class="bp">self</span><span class="o">.</span><span class="n">x</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">y</span> <span class="o">=</span> <span class="n">x</span><span class="p">,</span> <span class="n">y</span>

  822. <span class="gp">... </span>    <span class="k">def</span> <span class="fm">__str__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>

  823. <span class="gp">... </span>        <span class="k">return</span> <span class="s1">&#39;Point(</span><span class="si">{self.x}</span><span class="s1">, </span><span class="si">{self.y}</span><span class="s1">)&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="bp">self</span><span class="o">=</span><span class="bp">self</span><span class="p">)</span>

  824. <span class="gp">...</span>

  825. <span class="gp">&gt;&gt;&gt; </span><span class="nb">str</span><span class="p">(</span><span class="n">Point</span><span class="p">(</span><span class="mi">4</span><span class="p">,</span> <span class="mi">2</span><span class="p">))</span>

  826. <span class="go">&#39;Point(4, 2)&#39;</span>

  827. </pre></div>

  828. </div>

  829. <p>Accessing arguments’ items:</p>

  830. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">coord</span> <span class="o">=</span> <span class="p">(</span><span class="mi">3</span><span class="p">,</span> <span class="mi">5</span><span class="p">)</span>

  831. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;X: </span><span class="si">{0[0]}</span><span class="s1">;  Y: </span><span class="si">{0[1]}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">coord</span><span class="p">)</span>

  832. <span class="go">&#39;X: 3;  Y: 5&#39;</span>

  833. </pre></div>

  834. </div>

  835. <p>Replacing <code class="docutils literal notranslate"><span class="pre">%s</span></code> and <code class="docutils literal notranslate"><span class="pre">%r</span></code>:</p>

  836. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s2">&quot;repr() shows quotes: </span><span class="si">{!r}</span><span class="s2">; str() doesn&#39;t: </span><span class="si">{!s}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;test1&#39;</span><span class="p">,</span> <span class="s1">&#39;test2&#39;</span><span class="p">)</span>

  837. <span class="go">&quot;repr() shows quotes: &#39;test1&#39;; str() doesn&#39;t: test2&quot;</span>

  838. </pre></div>

  839. </div>

  840. <p>Aligning the text and specifying a width:</p>

  841. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:&lt;30}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;left aligned&#39;</span><span class="p">)</span>

  842. <span class="go">&#39;left aligned                  &#39;</span>

  843. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:&gt;30}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;right aligned&#39;</span><span class="p">)</span>

  844. <span class="go">&#39;                 right aligned&#39;</span>

  845. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:^30}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;centered&#39;</span><span class="p">)</span>

  846. <span class="go">&#39;           centered           &#39;</span>

  847. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:*^30}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="s1">&#39;centered&#39;</span><span class="p">)</span>  <span class="c1"># use &#39;*&#39; as a fill char</span>

  848. <span class="go">&#39;***********centered***********&#39;</span>

  849. </pre></div>

  850. </div>

  851. <p>Replacing <code class="docutils literal notranslate"><span class="pre">%+f</span></code>, <code class="docutils literal notranslate"><span class="pre">%-f</span></code>, and <code class="docutils literal notranslate"><span class="pre">%</span> <span class="pre">f</span></code> and specifying a sign:</p>

  852. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:+f}</span><span class="s1">; </span><span class="si">{:+f}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="mf">3.14</span><span class="p">,</span> <span class="o">-</span><span class="mf">3.14</span><span class="p">)</span>  <span class="c1"># show it always</span>

  853. <span class="go">&#39;+3.140000; -3.140000&#39;</span>

  854. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{: f}</span><span class="s1">; </span><span class="si">{: f}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="mf">3.14</span><span class="p">,</span> <span class="o">-</span><span class="mf">3.14</span><span class="p">)</span>  <span class="c1"># show a space for positive numbers</span>

  855. <span class="go">&#39; 3.140000; -3.140000&#39;</span>

  856. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:-f}</span><span class="s1">; </span><span class="si">{:-f}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="mf">3.14</span><span class="p">,</span> <span class="o">-</span><span class="mf">3.14</span><span class="p">)</span>  <span class="c1"># show only the minus -- same as &#39;{:f}; {:f}&#39;</span>

  857. <span class="go">&#39;3.140000; -3.140000&#39;</span>

  858. </pre></div>

  859. </div>

  860. <p>Replacing <code class="docutils literal notranslate"><span class="pre">%x</span></code> and <code class="docutils literal notranslate"><span class="pre">%o</span></code> and converting the value to different bases:</p>

  861. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="c1"># format also supports binary numbers</span>

  862. <span class="gp">&gt;&gt;&gt; </span><span class="s2">&quot;int: </span><span class="si">{0:d}</span><span class="s2">;  hex: </span><span class="si">{0:x}</span><span class="s2">;  oct: </span><span class="si">{0:o}</span><span class="s2">;  bin: </span><span class="si">{0:b}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span>

  863. <span class="go">&#39;int: 42;  hex: 2a;  oct: 52;  bin: 101010&#39;</span>

  864. <span class="gp">&gt;&gt;&gt; </span><span class="c1"># with 0x, 0o, or 0b as prefix:</span>

  865. <span class="gp">&gt;&gt;&gt; </span><span class="s2">&quot;int: </span><span class="si">{0:d}</span><span class="s2">;  hex: </span><span class="si">{0:#x}</span><span class="s2">;  oct: </span><span class="si">{0:#o}</span><span class="s2">;  bin: </span><span class="si">{0:#b}</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="mi">42</span><span class="p">)</span>

  866. <span class="go">&#39;int: 42;  hex: 0x2a;  oct: 0o52;  bin: 0b101010&#39;</span>

  867. </pre></div>

  868. </div>

  869. <p>Using the comma as a thousands separator:</p>

  870. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:,}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="mi">1234567890</span><span class="p">)</span>

  871. <span class="go">&#39;1,234,567,890&#39;</span>

  872. </pre></div>

  873. </div>

  874. <p>Expressing a percentage:</p>

  875. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">points</span> <span class="o">=</span> <span class="mi">19</span>

  876. <span class="gp">&gt;&gt;&gt; </span><span class="n">total</span> <span class="o">=</span> <span class="mi">22</span>

  877. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;Correct answers: </span><span class="si">{:.2%}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">points</span><span class="o">/</span><span class="n">total</span><span class="p">)</span>

  878. <span class="go">&#39;Correct answers: 86.36%&#39;</span>

  879. </pre></div>

  880. </div>

  881. <p>Using type-specific formatting:</p>

  882. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="kn">import</span> <span class="nn">datetime</span>

  883. <span class="gp">&gt;&gt;&gt; </span><span class="n">d</span> <span class="o">=</span> <span class="n">datetime</span><span class="o">.</span><span class="n">datetime</span><span class="p">(</span><span class="mi">2010</span><span class="p">,</span> <span class="mi">7</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">12</span><span class="p">,</span> <span class="mi">15</span><span class="p">,</span> <span class="mi">58</span><span class="p">)</span>

  884. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;{:%Y-%m-</span><span class="si">%d</span><span class="s1"> %H:%M:%S}&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">d</span><span class="p">)</span>

  885. <span class="go">&#39;2010-07-04 12:15:58&#39;</span>

  886. </pre></div>

  887. </div>

  888. <p>Nesting arguments and more complex examples:</p>

  889. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="k">for</span> <span class="n">align</span><span class="p">,</span> <span class="n">text</span> <span class="ow">in</span> <span class="nb">zip</span><span class="p">(</span><span class="s1">&#39;&lt;^&gt;&#39;</span><span class="p">,</span> <span class="p">[</span><span class="s1">&#39;left&#39;</span><span class="p">,</span> <span class="s1">&#39;center&#39;</span><span class="p">,</span> <span class="s1">&#39;right&#39;</span><span class="p">]):</span>

  890. <span class="gp">... </span>    <span class="s1">&#39;{0:</span><span class="si">{fill}{align}</span><span class="s1">16}&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">text</span><span class="p">,</span> <span class="n">fill</span><span class="o">=</span><span class="n">align</span><span class="p">,</span> <span class="n">align</span><span class="o">=</span><span class="n">align</span><span class="p">)</span>

  891. <span class="gp">...</span>

  892. <span class="go">&#39;left&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&#39;</span>

  893. <span class="go">&#39;^^^^^center^^^^^&#39;</span>

  894. <span class="go">&#39;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;right&#39;</span>

  895. <span class="gp">&gt;&gt;&gt;</span>

  896. <span class="gp">&gt;&gt;&gt; </span><span class="n">octets</span> <span class="o">=</span> <span class="p">[</span><span class="mi">192</span><span class="p">,</span> <span class="mi">168</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">1</span><span class="p">]</span>

  897. <span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="si">{:02X}{:02X}{:02X}{:02X}</span><span class="s1">&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="o">*</span><span class="n">octets</span><span class="p">)</span>

  898. <span class="go">&#39;C0A80001&#39;</span>

  899. <span class="gp">&gt;&gt;&gt; </span><span class="nb">int</span><span class="p">(</span><span class="n">_</span><span class="p">,</span> <span class="mi">16</span><span class="p">)</span>

  900. <span class="go">3232235521</span>

  901. <span class="gp">&gt;&gt;&gt;</span>

  902. <span class="gp">&gt;&gt;&gt; </span><span class="n">width</span> <span class="o">=</span> <span class="mi">5</span>

  903. <span class="gp">&gt;&gt;&gt; </span><span class="k">for</span> <span class="n">num</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span><span class="mi">12</span><span class="p">):</span> 

  904. <span class="gp">... </span>    <span class="k">for</span> <span class="n">base</span> <span class="ow">in</span> <span class="s1">&#39;dXob&#39;</span><span class="p">:</span>

  905. <span class="gp">... </span>        <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;{0:</span><span class="si">{width}{base}</span><span class="s1">}&#39;</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">num</span><span class="p">,</span> <span class="n">base</span><span class="o">=</span><span class="n">base</span><span class="p">,</span> <span class="n">width</span><span class="o">=</span><span class="n">width</span><span class="p">),</span> <span class="n">end</span><span class="o">=</span><span class="s1">&#39; &#39;</span><span class="p">)</span>

  906. <span class="gp">... </span>    <span class="nb">print</span><span class="p">()</span>

  907. <span class="gp">...</span>

  908. <span class="go">    5     5     5   101</span>

  909. <span class="go">    6     6     6   110</span>

  910. <span class="go">    7     7     7   111</span>

  911. <span class="go">    8     8    10  1000</span>

  912. <span class="go">    9     9    11  1001</span>

  913. <span class="go">   10     A    12  1010</span>

  914. <span class="go">   11     B    13  1011</span>

  915. </pre></div>

  916. </div>

  917. </section>

  918. </section>

  919. <section id="template-strings">

  920. <span id="id1"></span><h2>Template strings<a class="headerlink" href="#template-strings" title="Link to this heading">¶</a></h2>

  921. <p>Template strings provide simpler string substitutions as described in

  922. <span class="target" id="index-12"></span><a class="pep reference external" href="https://peps.python.org/pep-0292/"><strong>PEP 292</strong></a>.  A primary use case for template strings is for

  923. internationalization (i18n) since in that context, the simpler syntax and

  924. functionality makes it easier to translate than other built-in string

  925. formatting facilities in Python.  As an example of a library built on template

  926. strings for i18n, see the

  927. <a class="reference external" href="https://flufli18n.readthedocs.io/en/latest/">flufl.i18n</a> package.</p>

  928. <p id="index-13">Template strings support <code class="docutils literal notranslate"><span class="pre">$</span></code>-based substitutions, using the following rules:</p>

  929. <ul class="simple">

  930. <li><p><code class="docutils literal notranslate"><span class="pre">$$</span></code> is an escape; it is replaced with a single <code class="docutils literal notranslate"><span class="pre">$</span></code>.</p></li>

  931. <li><p><code class="docutils literal notranslate"><span class="pre">$identifier</span></code> names a substitution placeholder matching a mapping key of

  932. <code class="docutils literal notranslate"><span class="pre">&quot;identifier&quot;</span></code>.  By default, <code class="docutils literal notranslate"><span class="pre">&quot;identifier&quot;</span></code> is restricted to any

  933. case-insensitive ASCII alphanumeric string (including underscores) that

  934. starts with an underscore or ASCII letter.  The first non-identifier

  935. character after the <code class="docutils literal notranslate"><span class="pre">$</span></code> character terminates this placeholder

  936. specification.</p></li>

  937. <li><p><code class="docutils literal notranslate"><span class="pre">${identifier}</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">$identifier</span></code>.  It is required when

  938. valid identifier characters follow the placeholder but are not part of the

  939. placeholder, such as <code class="docutils literal notranslate"><span class="pre">&quot;${noun}ification&quot;</span></code>.</p></li>

  940. </ul>

  941. <p>Any other appearance of <code class="docutils literal notranslate"><span class="pre">$</span></code> in the string will result in a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a>

  942. being raised.</p>

  943. <p>The <a class="reference internal" href="#module-string" title="string: Common string operations."><code class="xref py py-mod docutils literal notranslate"><span class="pre">string</span></code></a> module provides a <a class="reference internal" href="#string.Template" title="string.Template"><code class="xref py py-class docutils literal notranslate"><span class="pre">Template</span></code></a> class that implements

  944. these rules.  The methods of <a class="reference internal" href="#string.Template" title="string.Template"><code class="xref py py-class docutils literal notranslate"><span class="pre">Template</span></code></a> are:</p>

  945. <dl class="py class">

  946. <dt class="sig sig-object py" id="string.Template">

  947. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">Template</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">template</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Template" title="Link to this definition">¶</a></dt>

  948. <dd><p>The constructor takes a single argument which is the template string.</p>

  949. <dl class="py method">

  950. <dt class="sig sig-object py" id="string.Template.substitute">

  951. <span class="sig-name descname"><span class="pre">substitute</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">mapping</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">{}</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">/</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">**</span></span><span class="n"><span class="pre">kwds</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Template.substitute" title="Link to this definition">¶</a></dt>

  952. <dd><p>Performs the template substitution, returning a new string.  <em>mapping</em> is

  953. any dictionary-like object with keys that match the placeholders in the

  954. template.  Alternatively, you can provide keyword arguments, where the

  955. keywords are the placeholders.  When both <em>mapping</em> and <em>kwds</em> are given

  956. and there are duplicates, the placeholders from <em>kwds</em> take precedence.</p>

  957. </dd></dl>

  958. 

  959. <dl class="py method">

  960. <dt class="sig sig-object py" id="string.Template.safe_substitute">

  961. <span class="sig-name descname"><span class="pre">safe_substitute</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">mapping</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">{}</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">/</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">**</span></span><span class="n"><span class="pre">kwds</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.Template.safe_substitute" title="Link to this definition">¶</a></dt>

  962. <dd><p>Like <a class="reference internal" href="#string.Template.substitute" title="string.Template.substitute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">substitute()</span></code></a>, except that if placeholders are missing from

  963. <em>mapping</em> and <em>kwds</em>, instead of raising a <a class="reference internal" href="exceptions.html#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">KeyError</span></code></a> exception, the

  964. original placeholder will appear in the resulting string intact.  Also,

  965. unlike with <a class="reference internal" href="#string.Template.substitute" title="string.Template.substitute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">substitute()</span></code></a>, any other appearances of the <code class="docutils literal notranslate"><span class="pre">$</span></code> will

  966. simply return <code class="docutils literal notranslate"><span class="pre">$</span></code> instead of raising <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a>.</p>

  967. <p>While other exceptions may still occur, this method is called “safe”

  968. because it always tries to return a usable string instead of

  969. raising an exception.  In another sense, <a class="reference internal" href="#string.Template.safe_substitute" title="string.Template.safe_substitute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">safe_substitute()</span></code></a> may be

  970. anything other than safe, since it will silently ignore malformed

  971. templates containing dangling delimiters, unmatched braces, or

  972. placeholders that are not valid Python identifiers.</p>

  973. </dd></dl>

  974. 

  975. <dl class="py method">

  976. <dt class="sig sig-object py" id="string.Template.is_valid">

  977. <span class="sig-name descname"><span class="pre">is_valid</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#string.Template.is_valid" title="Link to this definition">¶</a></dt>

  978. <dd><p>Returns false if the template has invalid placeholders that will cause

  979. <a class="reference internal" href="#string.Template.substitute" title="string.Template.substitute"><code class="xref py py-meth docutils literal notranslate"><span class="pre">substitute()</span></code></a> to raise <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a>.</p>

  980. <div class="versionadded">

  981. <p><span class="versionmodified added">New in version 3.11.</span></p>

  982. </div>

  983. </dd></dl>

  984. 

  985. <dl class="py method">

  986. <dt class="sig sig-object py" id="string.Template.get_identifiers">

  987. <span class="sig-name descname"><span class="pre">get_identifiers</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#string.Template.get_identifiers" title="Link to this definition">¶</a></dt>

  988. <dd><p>Returns a list of the valid identifiers in the template, in the order

  989. they first appear, ignoring any invalid identifiers.</p>

  990. <div class="versionadded">

  991. <p><span class="versionmodified added">New in version 3.11.</span></p>

  992. </div>

  993. </dd></dl>

  994. 

  995. <p><a class="reference internal" href="#string.Template" title="string.Template"><code class="xref py py-class docutils literal notranslate"><span class="pre">Template</span></code></a> instances also provide one public data attribute:</p>

  996. <dl class="py attribute">

  997. <dt class="sig sig-object py" id="string.Template.template">

  998. <span class="sig-name descname"><span class="pre">template</span></span><a class="headerlink" href="#string.Template.template" title="Link to this definition">¶</a></dt>

  999. <dd><p>This is the object passed to the constructor’s <em>template</em> argument.  In

  1000. general, you shouldn’t change it, but read-only access is not enforced.</p>

  1001. </dd></dl>

  1002. 

  1003. </dd></dl>

  1004. 

  1005. <p>Here is an example of how to use a Template:</p>

  1006. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="kn">from</span> <span class="nn">string</span> <span class="kn">import</span> <span class="n">Template</span>

  1007. <span class="gp">&gt;&gt;&gt; </span><span class="n">s</span> <span class="o">=</span> <span class="n">Template</span><span class="p">(</span><span class="s1">&#39;$who likes $what&#39;</span><span class="p">)</span>

  1008. <span class="gp">&gt;&gt;&gt; </span><span class="n">s</span><span class="o">.</span><span class="n">substitute</span><span class="p">(</span><span class="n">who</span><span class="o">=</span><span class="s1">&#39;tim&#39;</span><span class="p">,</span> <span class="n">what</span><span class="o">=</span><span class="s1">&#39;kung pao&#39;</span><span class="p">)</span>

  1009. <span class="go">&#39;tim likes kung pao&#39;</span>

  1010. <span class="gp">&gt;&gt;&gt; </span><span class="n">d</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">(</span><span class="n">who</span><span class="o">=</span><span class="s1">&#39;tim&#39;</span><span class="p">)</span>

  1011. <span class="gp">&gt;&gt;&gt; </span><span class="n">Template</span><span class="p">(</span><span class="s1">&#39;Give $who $100&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">substitute</span><span class="p">(</span><span class="n">d</span><span class="p">)</span>

  1012. <span class="gt">Traceback (most recent call last):</span>

  1013. <span class="c">...</span>

  1014. <span class="gr">ValueError</span>: <span class="n">Invalid placeholder in string: line 1, col 11</span>

  1015. <span class="gp">&gt;&gt;&gt; </span><span class="n">Template</span><span class="p">(</span><span class="s1">&#39;$who likes $what&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">substitute</span><span class="p">(</span><span class="n">d</span><span class="p">)</span>

  1016. <span class="gt">Traceback (most recent call last):</span>

  1017. <span class="c">...</span>

  1018. <span class="gr">KeyError</span>: <span class="n">&#39;what&#39;</span>

  1019. <span class="gp">&gt;&gt;&gt; </span><span class="n">Template</span><span class="p">(</span><span class="s1">&#39;$who likes $what&#39;</span><span class="p">)</span><span class="o">.</span><span class="n">safe_substitute</span><span class="p">(</span><span class="n">d</span><span class="p">)</span>

  1020. <span class="go">&#39;tim likes $what&#39;</span>

  1021. </pre></div>

  1022. </div>

  1023. <p>Advanced usage: you can derive subclasses of <a class="reference internal" href="#string.Template" title="string.Template"><code class="xref py py-class docutils literal notranslate"><span class="pre">Template</span></code></a> to customize

  1024. the placeholder syntax, delimiter character, or the entire regular expression

  1025. used to parse template strings.  To do this, you can override these class

  1026. attributes:</p>

  1027. <ul>

  1028. <li><p><em>delimiter</em> – This is the literal string describing a placeholder

  1029. introducing delimiter.  The default value is <code class="docutils literal notranslate"><span class="pre">$</span></code>.  Note that this should

  1030. <em>not</em> be a regular expression, as the implementation will call

  1031. <a class="reference internal" href="re.html#re.escape" title="re.escape"><code class="xref py py-meth docutils literal notranslate"><span class="pre">re.escape()</span></code></a> on this string as needed.  Note further that you cannot

  1032. change the delimiter after class creation (i.e. a different delimiter must

  1033. be set in the subclass’s class namespace).</p></li>

  1034. <li><p><em>idpattern</em> – This is the regular expression describing the pattern for

  1035. non-braced placeholders.  The default value is the regular expression

  1036. <code class="docutils literal notranslate"><span class="pre">(?a:[_a-z][_a-z0-9]*)</span></code>.  If this is given and <em>braceidpattern</em> is

  1037. <code class="docutils literal notranslate"><span class="pre">None</span></code> this pattern will also apply to braced placeholders.</p>

  1038. <div class="admonition note">

  1039. <p class="admonition-title">Note</p>

  1040. <p>Since default <em>flags</em> is <code class="docutils literal notranslate"><span class="pre">re.IGNORECASE</span></code>, pattern <code class="docutils literal notranslate"><span class="pre">[a-z]</span></code> can match

  1041. with some non-ASCII characters. That’s why we use the local <code class="docutils literal notranslate"><span class="pre">a</span></code> flag

  1042. here.</p>

  1043. </div>

  1044. <div class="versionchanged">

  1045. <p><span class="versionmodified changed">Changed in version 3.7: </span><em>braceidpattern</em> can be used to define separate patterns used inside and

  1046. outside the braces.</p>

  1047. </div>

  1048. </li>

  1049. <li><p><em>braceidpattern</em> – This is like <em>idpattern</em> but describes the pattern for

  1050. braced placeholders.  Defaults to <code class="docutils literal notranslate"><span class="pre">None</span></code> which means to fall back to

  1051. <em>idpattern</em> (i.e. the same pattern is used both inside and outside braces).

  1052. If given, this allows you to define different patterns for braced and

  1053. unbraced placeholders.</p>

  1054. <div class="versionadded">

  1055. <p><span class="versionmodified added">New in version 3.7.</span></p>

  1056. </div>

  1057. </li>

  1058. <li><p><em>flags</em> – The regular expression flags that will be applied when compiling

  1059. the regular expression used for recognizing substitutions.  The default value

  1060. is <code class="docutils literal notranslate"><span class="pre">re.IGNORECASE</span></code>.  Note that <code class="docutils literal notranslate"><span class="pre">re.VERBOSE</span></code> will always be added to the

  1061. flags, so custom <em>idpattern</em>s must follow conventions for verbose regular

  1062. expressions.</p>

  1063. <div class="versionadded">

  1064. <p><span class="versionmodified added">New in version 3.2.</span></p>

  1065. </div>

  1066. </li>

  1067. </ul>

  1068. <p>Alternatively, you can provide the entire regular expression pattern by

  1069. overriding the class attribute <em>pattern</em>.  If you do this, the value must be a

  1070. regular expression object with four named capturing groups.  The capturing

  1071. groups correspond to the rules given above, along with the invalid placeholder

  1072. rule:</p>

  1073. <ul class="simple">

  1074. <li><p><em>escaped</em> – This group matches the escape sequence, e.g. <code class="docutils literal notranslate"><span class="pre">$$</span></code>, in the

  1075. default pattern.</p></li>

  1076. <li><p><em>named</em> – This group matches the unbraced placeholder name; it should not

  1077. include the delimiter in capturing group.</p></li>

  1078. <li><p><em>braced</em> – This group matches the brace enclosed placeholder name; it should

  1079. not include either the delimiter or braces in the capturing group.</p></li>

  1080. <li><p><em>invalid</em> – This group matches any other delimiter pattern (usually a single

  1081. delimiter), and it should appear last in the regular expression.</p></li>

  1082. </ul>

  1083. <p>The methods on this class will raise <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> if the pattern matches

  1084. the template without one of these named groups matching.</p>

  1085. </section>

  1086. <section id="helper-functions">

  1087. <h2>Helper functions<a class="headerlink" href="#helper-functions" title="Link to this heading">¶</a></h2>

  1088. <dl class="py function">

  1089. <dt class="sig sig-object py" id="string.capwords">

  1090. <span class="sig-prename descclassname"><span class="pre">string.</span></span><span class="sig-name descname"><span class="pre">capwords</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">s</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">sep</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#string.capwords" title="Link to this definition">¶</a></dt>

  1091. <dd><p>Split the argument into words using <a class="reference internal" href="stdtypes.html#str.split" title="str.split"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.split()</span></code></a>, capitalize each word

  1092. using <a class="reference internal" href="stdtypes.html#str.capitalize" title="str.capitalize"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.capitalize()</span></code></a>, and join the capitalized words using

  1093. <a class="reference internal" href="stdtypes.html#str.join" title="str.join"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.join()</span></code></a>.  If the optional second argument <em>sep</em> is absent

  1094. or <code class="docutils literal notranslate"><span class="pre">None</span></code>, runs of whitespace characters are replaced by a single space

  1095. and leading and trailing whitespace are removed, otherwise <em>sep</em> is used to

  1096. split and join the words.</p>

  1097. </dd></dl>

  1098. 

  1099. </section>

  1100. </section>

  1101. 

  1102. 

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  1108.         <div class="sphinxsidebarwrapper">

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  1110.     <h3><a href="../contents.html">Table of Contents</a></h3>

  1111.     <ul>

  1112. <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">string</span></code> — Common string operations</a><ul>

  1113. <li><a class="reference internal" href="#string-constants">String constants</a></li>

  1114. <li><a class="reference internal" href="#custom-string-formatting">Custom String Formatting</a></li>

  1115. <li><a class="reference internal" href="#format-string-syntax">Format String Syntax</a><ul>

  1116. <li><a class="reference internal" href="#format-specification-mini-language">Format Specification Mini-Language</a></li>

  1117. <li><a class="reference internal" href="#format-examples">Format examples</a></li>

  1118. </ul>

  1119. </li>

  1120. <li><a class="reference internal" href="#template-strings">Template strings</a></li>

  1121. <li><a class="reference internal" href="#helper-functions">Helper functions</a></li>

  1122. </ul>

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