Regular Expressions 101

Save & Share

  • Regex Version: ver. 9
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gim

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "^(?:[\\s]+)?(?:const|let|var|)?(?:[a-z0-9.]+(?:\\.prototype)?)?(?:\\s)?(?:[a-z0-9-_\\{\\}:\\s]+\\s?=)?\\s?(?:[a-z0-9]+\\s+\\:\\s+)?(?:function\\s?)?(?:[a-z0-9_-]+)?\\s?\\(.*\\)\\s?(?:.+)?([=>]:)?\\{(?:(?:[^\\}\\{]+|\\{(?:[^\\}\\{]+|\\{[^\\}\\{]*\\})*\\})*\\}(?:\\s?\\(.*\\)\\s?\\)\\s?)?)?(?:\\;)?$"; final String string = "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n\n\n" + "const a = {\n" + " apples() {\n\n" + " },\n" + " apples2 : function() {\n" + " },\n" + " apples3 : () => {\n" + " }\n" + "}\n\n" + "function(){}\n\n" + "function() {}\n\n" + "function() { }\n" + "function () { }\n" + "function (arg, asdf) { }\n" + "function (arg, asdf):Typings { }\n" + "function (arg, asdf):something<Else> { }\n\n" + "function () { }\n" + "const x = function () { }\n" + "const { x } = function () { }\n\n" + "const { x: asdf } = function () { }\n\n" + "const filterFn = () => {}\n\n" + "// won't grab\n" + "const filterFn = apples.filter(() => {});\n" + "// won't grab\n" + "const filterFn = apples.filter(function(){});\n\n\n\n" + "class Bla {\n" + " constructor() {\n" + " }\n" + " someMethod1() {\n" + " }\n" + " someMethod2() => {\n" + " }\n" + " get someMethod3() {\n" + " }\n" + "}\n\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "HoverBoard.prototype.getFormatValueIfExists = function (prop, defaultValue) {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "const getFormatValueIfExists = function (prop, defaultValue) {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + " var getFormatValueIfExists = (prop, defaultValue) => {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "window.x = (prop, defaultValue) => {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "something.else.x = (prop, defaultValue) => {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "var x = null;\n" + "x = (prop, defaultValue) => {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "function getFormatValueIfExists(prop, defaultValue) {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "function (prop, defaultValue) {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "(prop, defaultValue) => {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "};\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "((prop, defaultValue) => {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "}());\n\n\n\n\n" + "/**\n" + " * @function\n" + " * @description simple method that tries to retrieve a config value from the format\n" + " * if it exists, else it will return the second argument as the default value.\n" + " * @param {string} prop - the prop name to retrieve\n" + " * @param {any} defaultValue - the value to use if we can't extract from the format\n" + " * @returns {any} - the default value or extracted format value\n" + " */\n" + "((prop, defaultValue) => {\n" + " try {\n" + " return typeof this.config.formats[this.name][prop] !== 'undefined' ? this.config.formats[self.name][prop] : defaultValue;\n" + " } catch (e) {\n" + " return defaultValue;\n" + " }\n" + "} (window) );\n\n"; final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE | Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(i)); } } } }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html