{"id":1900,"date":"2023-06-01T07:33:37","date_gmt":"2023-06-01T00:33:37","guid":{"rendered":"https:\/\/csharptutorial.net\/?page_id=1900"},"modified":"2023-06-01T07:35:05","modified_gmt":"2023-06-01T00:35:05","slug":"csharp-regex-character-classes","status":"publish","type":"page","link":"https:\/\/www.csharptutorial.net\/csharp-regular-expression\/csharp-regex-character-classes\/","title":{"rendered":"C# Regex Character Classes"},"content":{"rendered":"\n<p><strong>Summary<\/strong>: in this tutorial, you will learn how to use character classes in regular expressions using C#. <\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Introduction to the C# Regex Character Classes<\/h2>\n\n\n\n<p>Character classes define a set of characters. For example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Digits (0 to 9 )<\/li>\n\n\n\n<li>Alphabets (a to z)<\/li>\n\n\n\n<li>Whitespace  (tab, space, &#8230;)<\/li>\n<\/ul>\n\n\n\n<p>Character classes allow you to match characters from a specified set of characters.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\\d: digit character class<\/h3>\n\n\n\n<p>The <code>\\d <\/code>represents the digit character class that matches any single digit from 0 to 9. The following example uses the <code>\\d<\/code> character class to find all digits in a string:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-1\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">using<\/span> System.Text.RegularExpressions;\r\n<span class=\"hljs-keyword\">using<\/span> <span class=\"hljs-keyword\">static<\/span> System.Console;\r\n\r\n\r<span class=\"hljs-keyword\">var<\/span> text = <span class=\"hljs-string\">\"7 Awesome New Features in C# 12\"<\/span>;\r\n<span class=\"hljs-keyword\">var<\/span> pattern = <span class=\"hljs-string\">@\"\\d\"<\/span>;\r\n\r\n<span class=\"hljs-keyword\">var<\/span> matches = Regex.Matches(text, pattern);\r\n\r\n<span class=\"hljs-keyword\">foreach<\/span> (<span class=\"hljs-keyword\">var<\/span> match <span class=\"hljs-keyword\">in<\/span> matches)\r\n{\r\n    WriteLine(match);\r\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-1\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/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\">3\n1\n2<\/code><\/span><\/pre>\n\n\n<p>To match two digits, you use <code>\\d\\d<\/code> like this:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-2\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">using<\/span> System.Text.RegularExpressions;\r\n<span class=\"hljs-keyword\">using<\/span> <span class=\"hljs-keyword\">static<\/span> System.Console;\r\n\r\n\r<span class=\"hljs-keyword\">var<\/span> text = <span class=\"hljs-string\">\"3 Awesome New Features in C# 12\"<\/span>;\r\n<span class=\"hljs-keyword\">var<\/span> pattern = <span class=\"hljs-string\">@\"\\d\\d\"<\/span>;\r\n\r\n<span class=\"hljs-keyword\">var<\/span> matches = Regex.Matches(text, pattern);\r\n\r\n<span class=\"hljs-keyword\">foreach<\/span> (<span class=\"hljs-keyword\">var<\/span> match <span class=\"hljs-keyword\">in<\/span> matches)\r\n{\r\n    WriteLine(match);\r\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-2\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/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\">12<\/code><\/span><\/pre>\n\n\n<p>In this example, the <code>\\d\\d<\/code> matches 12, not 3. <\/p>\n\n\n\n<p>Notice that you&#8217;ll learn how to use the quantifiers to make the character class more concise like this \\d{2}<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\\w: the word character class<\/h3>\n\n\n\n<p>The <code>\\w<\/code> represents the word character class that matches a single ASCII character including the alphabets, digits, underscores (_)<\/p>\n\n\n\n<p>The following example shows how to use the <code>\\w<\/code> character class to match all word characters from a string:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-3\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">using<\/span> System.Text.RegularExpressions;\r\n<span class=\"hljs-keyword\">using<\/span> <span class=\"hljs-keyword\">static<\/span> System.Console;\r\n\r\n\r\n<span class=\"hljs-keyword\">var<\/span> text = <span class=\"hljs-string\">\"C# is awesome\"<\/span>;\r\n<span class=\"hljs-keyword\">var<\/span> pattern = <span class=\"hljs-string\">@\"\\w\"<\/span>;\r\n\r\n<span class=\"hljs-keyword\">var<\/span> matches = Regex.Matches(text, pattern);\r\n\r\n<span class=\"hljs-keyword\">foreach<\/span> (<span class=\"hljs-keyword\">var<\/span> match <span class=\"hljs-keyword\">in<\/span> matches)\r\n{\r\n    WriteLine(match);\r\n}\n<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-3\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-4\" data-shcb-language-name=\"plaintext\" data-shcb-language-slug=\"plaintext\"><span><code class=\"hljs language-plaintext\">C\r\ni\r\ns\r\na\r\nw\r\ne\r\ns\r\no\r\nm\r\ne<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-4\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">plaintext<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">plaintext<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<h3 class=\"wp-block-heading\">\\s: whitespace character class<\/h3>\n\n\n\n<p>The <code>\\s<\/code> represents the whitespace character class that includes newline, tab, vertical tab, space, etc. The following example uses the <code>\\s<\/code> character class to match whitespace characters in a string:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-5\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">using<\/span> System.Text.RegularExpressions;\r\n<span class=\"hljs-keyword\">using<\/span> <span class=\"hljs-keyword\">static<\/span> System.Console;\r\n\r\n\r<span class=\"hljs-keyword\">var<\/span> text = <span class=\"hljs-string\">\"C# is awesome!\"<\/span>;\r\n<span class=\"hljs-keyword\">var<\/span> pattern = <span class=\"hljs-string\">@\"\\s\"<\/span>;\r\n\r\n<span class=\"hljs-keyword\">var<\/span> matches = Regex.Matches(text, pattern);\r\n\r\nWriteLine(<span class=\"hljs-string\">$\"<span class=\"hljs-subst\">{matches.Count}<\/span> matches found\"<\/span>);\r\n\r\n<span class=\"hljs-keyword\">foreach<\/span> (<span class=\"hljs-keyword\">var<\/span> match <span class=\"hljs-keyword\">in<\/span> matches)\r\n{\r\n    WriteLine(match);\r\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-5\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/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\">2 matches found\r\n\r\n\r\n<\/code><\/span><\/pre>\n\n\n<p>It returns two matches that correspond to the two spaces in the string.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Inverse character classes<\/h2>\n\n\n\n<p>Inverse character classes are also called negated character classes. They allow you to match any character that is not a specified set of characters. For example, an inverse character class of the digit character class matches any single character except for a digit.<\/p>\n\n\n\n<p>The flowing table displays character classes and their inverse versions:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Character class<\/th><th>Inverse character class<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td><code>\\d<\/code><\/td><td><code>\\D<\/code><\/td><td>Match any character, excluding digits<\/td><\/tr><tr><td><code>\\w<\/code><\/td><td><code>\\W<\/code><\/td><td>Match any character that is not a word character<\/td><\/tr><tr><td><code>\\s<\/code><\/td><td><code>\\S<\/code><\/td><td>Match any character, excluding whitespaces<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>For example, the following uses the <code>\\D<\/code> character class to match the non-digit character of a phone number:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-6\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">using<\/span> System.Text.RegularExpressions;\r\n<span class=\"hljs-keyword\">using<\/span> <span class=\"hljs-keyword\">static<\/span> System.Console;\r\n\r\n\r<span class=\"hljs-keyword\">var<\/span> phone = <span class=\"hljs-string\">\"+1-(408)-555-6666\"<\/span>;\r\n<span class=\"hljs-keyword\">var<\/span> pattern = <span class=\"hljs-string\">@\"\\D\"<\/span>;\r\n\r\n<span class=\"hljs-keyword\">var<\/span> matches = Regex.Matches(phone, pattern);\r\n\r\n\r\n<span class=\"hljs-keyword\">foreach<\/span> (<span class=\"hljs-keyword\">var<\/span> match <span class=\"hljs-keyword\">in<\/span> matches)\r\n{\r\n    WriteLine(match);\r\n}<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-6\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>Output:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-7\" data-shcb-language-name=\"plaintext\" data-shcb-language-slug=\"plaintext\"><span><code class=\"hljs language-plaintext\">+\r\n-\r\n(\r\n)\r\n-\r\n-<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-7\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">plaintext<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">plaintext<\/span><span class=\"shcb-language__paren\">)<\/span><\/small><\/pre>\n\n\n<p>To turn the phone number from <code>+1-(408)-555-6666<\/code> format to <code>14085556666<\/code>, you use the <code>Replace()<\/code> method of the <code><a href=\"https:\/\/csharptutorial.net\/csharp-regular-expression\/csharp-regex\/\">Regex<\/a><\/code> class:<\/p>\n\n\n<pre class=\"wp-block-code\" aria-describedby=\"shcb-language-8\" data-shcb-language-name=\"C#\" data-shcb-language-slug=\"cs\"><span><code class=\"hljs language-cs\"><span class=\"hljs-keyword\">using<\/span> System.Text.RegularExpressions;\r\n<span class=\"hljs-keyword\">using<\/span> <span class=\"hljs-keyword\">static<\/span> System.Console;\r\n\r\n\r<span class=\"hljs-keyword\">var<\/span> phone = <span class=\"hljs-string\">\"+1-(408)-555-6666\"<\/span>;\r\n<span class=\"hljs-keyword\">var<\/span> pattern = <span class=\"hljs-string\">@\"\\D\"<\/span>;\r\n\r\n<span class=\"hljs-keyword\">var<\/span> result = Regex.Replace(phone, pattern, <span class=\"hljs-string\">\"\"<\/span>);\r\n\r\nWriteLine(result);<\/code><\/span><small class=\"shcb-language\" id=\"shcb-language-8\"><span class=\"shcb-language__label\">Code language:<\/span> <span class=\"shcb-language__name\">C#<\/span> <span class=\"shcb-language__paren\">(<\/span><span class=\"shcb-language__slug\">cs<\/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\">14085556666<\/code><\/span><\/pre>\n\n\n<h2 class=\"wp-block-heading\">Summary<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A character class defines a set of characters.<\/li>\n\n\n\n<li><code>\\d<\/code> represents the digit character class.<\/li>\n\n\n\n<li><code>\\w<\/code> represents the word character class.<\/li>\n\n\n\n<li><code>\\s<\/code> represents the whitespace character class.<\/li>\n\n\n\n<li><code>\\D<\/code>, <code>\\W<\/code>, <code>\\S<\/code> are inverse character classes of the <code>\\d<\/code>, <code>\\w<\/code>, <code>\\s<\/code>, which matches any character excluding the characters defined in the set.<\/li>\n<\/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 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Introduction to the C# Regex Character Classes Character classes define a set of characters. For example: Character classes allow you to match characters from a specified set of characters. \\d: digit character class The \\d represents the digit [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1892,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1900","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/pages\/1900","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/comments?post=1900"}],"version-history":[{"count":2,"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/pages\/1900\/revisions"}],"predecessor-version":[{"id":1902,"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/pages\/1900\/revisions\/1902"}],"up":[{"embeddable":true,"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/pages\/1892"}],"wp:attachment":[{"href":"https:\/\/www.csharptutorial.net\/wp-json\/wp\/v2\/media?parent=1900"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}