{"id":3182,"date":"2021-11-30T07:51:52","date_gmt":"2021-11-30T07:51:52","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=3182"},"modified":"2021-12-03T08:27:08","modified_gmt":"2021-12-03T08:27:08","slug":"python-regex-sets-ranges","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-regex\/python-regex-sets-ranges\/","title":{"rendered":"Python Regex Sets &#038; Ranges"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you&#8217;ll learn how to use the sets and ranges to create patterns that match a set of characters.<\/p>\n\n\n\n<p>Several characters or character sets inside square brackets <code>[]<\/code> mean matching for any character or character set among them.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='sets'>Sets <a href=\"#sets\" class=\"anchor\" id=\"sets\" title=\"Anchor for Sets\">#<\/a><\/h2>\n\n\n\n<p>For example, <code>[abc]<\/code> means any of three characters. <code>'a'<\/code>, <code>'b'<\/code>, or <code>'c'<\/code>. The <code>[abc]<\/code> is called a set. And you can use the set with regular characters to construct a search pattern.<\/p>\n\n\n\n<p>For example, the following program uses the pattern <code>licen[cs]e<\/code> that matches both <code>license<\/code> and <code>licence<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"PHP\" data-shcb-language-slug=\"php\"><span><code class=\"hljs language-php\">import re\n\ns = <span class=\"hljs-string\">'A licence or license'<\/span>\n\npattern = <span class=\"hljs-string\">'licen&#91;cs]e'<\/span>\nmatches = re.finditer(pattern, s)\n\n<span class=\"hljs-keyword\">for<\/span> match in matches:\n    <span class=\"hljs-keyword\">print<\/span>(match.group())<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">PHP<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">php<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\">licence\nlicense<\/code><\/span><\/pre>\n\n\n<p>The pattern <code>licen[cs]e<\/code> searches for:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><code>licen<\/code><\/li><li>then one of the letters <code>[cs]<\/code><\/li><li>then <code>e<\/code>.<\/li><\/ul>\n\n\n\n<p>Therefore, it matches <code>license<\/code> and <code>licence<\/code>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='ranges'>Ranges <a href=\"#ranges\" class=\"anchor\" id=\"ranges\" title=\"Anchor for Ranges\">#<\/a><\/h2>\n\n\n\n<p>When a set consists of many characters in e.g., from <code>a<\/code> to <code>z<\/code> or <code>1<\/code> to <code>9<\/code>, it&#8217;ll tedious to list them in a set. Instead, you can use character ranges in square brackets. For example, <code>[a-z]<\/code> is a character in the range from <code>a<\/code> to <code>z<\/code> and <code>[0-9]<\/code> is a digit from <code>0<\/code> to <code>9<\/code>.<\/p>\n\n\n\n<p>Also, you can use multiple ranges within the same square brackets. For example, <code>[a-z0-9]<\/code> has two ranges that match for a character that is either from <code>a<\/code> to <code>z<\/code> or a digit from <code>0<\/code> to <code>9<\/code>.<\/p>\n\n\n\n<p>Similarly, you can use one or more character sets inside the square brackets like <code>[\\d\\s]<\/code> means a digit or a space character.<\/p>\n\n\n\n<p>Likewise, you can mix the character with character sets. For example, <code>[\\d_]<\/code> matches for a digit or an underscore.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id='excluding-sets-ranges'>Excluding sets &amp; ranges <a href=\"#excluding-sets-ranges\" class=\"anchor\" id=\"excluding-sets-ranges\" title=\"Anchor for Excluding sets &amp; ranges\">#<\/a><\/h2>\n\n\n\n<p>To negate a set or a range, you use the caret character (<code>^<\/code>) at the beginning of the set and range. For example, the range <code>[^0-9]<\/code> matches any character except a digit. It is the same as the character set <code>\\D<\/code>.<\/p>\n\n\n\n<p>Notice that regex also uses the caret (<code>^<\/code>) as an anchor that matches at the beginning of a string. However, if you use the caret (<code>^<\/code>) inside the square brackets, the regex will treat it as a negation operator, not an anchor.<\/p>\n\n\n\n<p>The following example uses the caret (<code>^<\/code>) to negate the set <code>[aeoiu]<\/code> to match the consonants in the string <code>'Python'<\/code>:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"JavaScript\" data-shcb-language-slug=\"javascript\"><span><code class=\"hljs language-javascript\"><span class=\"hljs-keyword\">import<\/span> re\n\ns = <span class=\"hljs-string\">'Python'<\/span>\n\npattern = <span class=\"hljs-string\">'&#91;^aeoiu]'<\/span>\nmatches = re.finditer(pattern, s)\n\n<span class=\"hljs-keyword\">for<\/span> match <span class=\"hljs-keyword\">in<\/span> matches:\n    print(match.group())\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">JavaScript<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">javascript<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\"><span><code class=\"hljs\">P\ny\nt\nh\nn<\/code><\/span><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id='summary'>Summary <a href=\"#summary\" class=\"anchor\" id=\"summary\" title=\"Anchor for Summary\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>A set or a range matches any single character or character set specified in square brackets [&#8230;].<\/li><li>Use the caret (<code>^<\/code>) operator to negate a set or a range like <code>[^...]<\/code>.<\/li><\/ul>\n<div class=\"helpful-block-content\" data-title=\"\">\n\t<header>\n\t\t<div class=\"wth-question\">Was this tutorial helpful ?<\/div>\n\t\t<div class=\"wth-thumbs\">\n\t\t\t<button\n\t\t\t\tdata-post=\"3182\"\n\t\t\t\tdata-post-url=\"https:\/\/www.pythontutorial.net\/python-regex\/python-regex-sets-ranges\/\"\n\t\t\t\tdata-post-title=\"Python Regex Sets &#038; 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