{"id":4692,"date":"2020-04-01T09:11:39","date_gmt":"2020-04-01T09:11:39","guid":{"rendered":"https:\/\/www.askpython.com\/?p=4692"},"modified":"2022-07-07T07:07:57","modified_gmt":"2022-07-07T07:07:57","slug":"python-isidentifier-method","status":"publish","type":"post","link":"https:\/\/www.askpython.com\/python\/string\/python-isidentifier-method","title":{"rendered":"Python isidentifier() Method"},"content":{"rendered":"\n<p>So today in this tutorial, we are going to go through<strong> the Python isidentifier() method<\/strong>. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Introduction<\/h2>\n\n\n\n<p>Basically, an <a aria-label=\"identifier (opens in a new tab)\" rel=\"noreferrer noopener\" href=\"https:\/\/docs.python.org\/3.1\/reference\/lexical_analysis.html#identifiers\" target=\"_blank\" class=\"rank-math-link\">identifier<\/a> is a name given to any variable, class, object, function, etc by the user. These names are important to uniquely identify individual variables, classes etc.<\/p>\n\n\n\n<p>Hence, naming is a very important part of any variable, class, function, object, etc declaration. Python restricts the user and provides some basic guidelines for this naming procedure. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Understanding the Python isidentifier() Method<\/h2>\n\n\n\n<p>The <code>isidentifier()<\/code> method checks whether the provided string is eligible to be an identifier or not, and accordingly returns <strong>true<\/strong> if it is so, or <strong>false<\/strong> if it isn&#8217;t. <\/p>\n\n\n\n<p>The syntax for using the Python <code>isidentifier() <\/code>method is given below. <\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; title: ; notranslate\" title=\"\">\nresult = str.isidentifier()\n<\/pre><\/div>\n\n\n<p>Here,<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>result<\/strong> stores the boolean value (true or false) returned by the method,<\/li><li><strong>str<\/strong> is the string for which we need to check whether it is an identifier or not. <\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Working with the Python isidentifier() Method<\/h2>\n\n\n\n<p>Now that we have a basic understanding of the concept of identifiers and the Python <code>isidentifier()<\/code> method, let us take some examples to understand the working of the method. <\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; title: ; notranslate\" title=\"\">\nstring1 = &quot;Askpython&quot;\nprint(f&quot;Is {string1} a valid identifier? &quot;, string1.isidentifier())\n\nstring2 = &quot;i&quot; #an identifier may be of any length &gt; 0\nprint(f&quot;Is {string2} a valid identifier? &quot;, string2.isidentifier())\n\nstring3 = &quot;&quot; #short length not allowed\nprint(f&quot;Is {string3} a valid identifier? &quot;, string3.isidentifier())\n\nstring4 = &quot;_abcd1234&quot; #an identifier may start with an underscore\nprint(f&quot;Is {string4} a valid identifier? &quot;, string4.isidentifier())\n\nstring5 = &quot;1976&quot; #strings starting with numbers are not identifiers\nprint(f&quot;Is {string5} a valid identifier? &quot;, string5.isidentifier())\n<\/pre><\/div>\n\n\n<p><strong>Output<\/strong>:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: python; title: ; notranslate\" title=\"\">\nIs Askpython a valid identifier?  True\nIs i a valid identifier?  True\nIs  a valid identifier?  False\nIs _abcd1234 a valid identifier?  True\nIs 1976 a valid identifier?  False\n<\/pre><\/div>\n\n\n<p>Here,<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>For <strong>string1<\/strong> &#8211; &#8216;Askpython&#8217; is a valid identifier as it starts with a character, as well as doesn&#8217;t contain any special characters, <\/li><li>For <strong>string2<\/strong> &#8211; &#8216;i&#8217; is an valid identifier as it doesn&#8217;t contain any special characters as well as is of sufficient length, <\/li><li>For <strong>string3<\/strong> &#8211; the string doesn&#8217;t contain any character hence has a length 0. There should be at least one character inside a string for being eligible as an identifier, <\/li><li>For <strong>string4<\/strong> &#8211; it is a valid identifier as it starts with an underscore(&#8216;_&#8217;) and contains both characters and numbers, <\/li><li>For <strong>string5<\/strong> &#8211; &#8216;1976&#8217; is not a valid identifier as it starts with a number. <\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p>So that&#8217;s it for this tutorial. We learned about the built-in Python <code>isidentifier()<\/code> method. We highly recommend the readers go through the below reference links. The isidentifier() method is a <a href=\"https:\/\/www.askpython.com\/python\/string\" class=\"rank-math-link\">Python string<\/a> method.<\/p>\n\n\n\n<p>For any further questions, feel free to contact using the comments below.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">References<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li><a aria-label=\"String isidentifier() (opens in a new tab)\" class=\"rank-math-link rank-math-link\" rel=\"noreferrer noopener\" href=\"https:\/\/docs.python.org\/3.3\/library\/stdtypes.html?highlight=isidentifier#str.isidentifier\" target=\"_blank\">String isidentifier()<\/a> &#8211; Python Documentation,<\/li><li><a aria-label=\"Identifiers (opens in a new tab)\" class=\"rank-math-link rank-math-link\" rel=\"noreferrer noopener\" href=\"https:\/\/docs.python.org\/3.1\/reference\/lexical_analysis.html#identifiers\" target=\"_blank\">Identifiers and Keywords<\/a> &#8211; Python Documentation,<\/li><li>Supporting Non-ASCII Identifiers &#8211; <a rel=\"noreferrer noopener\" href=\"https:\/\/peps.python.org\/pep-3131\/\" target=\"_blank\">PEP-3131<\/a>,<\/li><li><a href=\"https:\/\/stackoverflow.com\/questions\/36330860\/pythonically-check-if-a-variable-name-is-valid\" target=\"_blank\" rel=\"noopener\">Pythonically check if a variable name is valid<\/a> &#8211; StackOverflow Question.<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"<p>So today in this tutorial, we are going to go through the Python isidentifier() method. Introduction Basically, an identifier is a name given to any variable, class, object, function, etc by the user. These names are important to uniquely identify individual variables, classes etc. Hence, naming is a very important part of any variable, class, [&hellip;]<\/p>\n","protected":false},"author":10,"featured_media":4697,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-4692","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-string"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts\/4692","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/comments?post=4692"}],"version-history":[{"count":0,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/posts\/4692\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/media\/4697"}],"wp:attachment":[{"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/media?parent=4692"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/categories?post=4692"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.askpython.com\/wp-json\/wp\/v2\/tags?post=4692"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}