Regular Expressions 101

Save & Share

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

/
/
gsU

Test String

Code Generator

Generated Code

#include <StringConstants.au3> ; to declare the Constants of StringRegExp #include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate Local $sRegex = "(?sU)<([^\/> ]+?)\s*?([^>]*)\s*(?:\/>|>(.*)<\/\1>)" Local $sString = " <?xml version="1.0"?>" & @CRLF & _ " <Name attribute = "value" attribute2="value2" >Convert number to string</Name>" & @CRLF & _ " <CommandLine>Examp1.EXE</CommandLine>" & @CRLF & _ " <Input>1</Input>" & @CRLF & _ " <Output>One</Output>" & @CRLF & _ " <Test TestId="0002" TestType="CMD">" & @CRLF & _ " <Name>Find succeeding characters</Name>" & @CRLF & _ " <CommandLine>Examp2.EXE</CommandLine>" & @CRLF & _ " <Input>abc</Input>" & @CRLF & _ " <Output>def</Output>" & @CRLF & _ " </Test>" & @CRLF & _ " <Test TestId="0003" TestType="GUI">" & @CRLF & _ " <Name>Convert multiple numbers to strings</Name>" & @CRLF & _ " <CommandLine>Examp2.EXE /Verbose</CommandLine>" & @CRLF & _ " <Input>123</Input>" & @CRLF & _ " <Output>One Two Three</Output>" & @CRLF & _ " </Test>" & @CRLF & _ " <Test TestId="0004" TestType="GUI">" & @CRLF & _ " <Name>Find correlated key</Name>" & @CRLF & _ " <CommandLine>Examp3.EXE</CommandLine>" & @CRLF & _ " <Input>a1</Input>" & @CRLF & _ " <Output>b1</Output>" & @CRLF & _ " </Test>" & @CRLF & _ " <Test TestId="0005" TestType="GUI">" & @CRLF & _ " <Name>Count characters</Name>" & @CRLF & _ " <CommandLine>FinalExamp.EXE</CommandLine>" & @CRLF & _ " <Input>This is a test</Input>" & @CRLF & _ " <Output>14</Output>" & @CRLF & _ " </Test>" & @CRLF & _ " <Test TestId="0006" TestType="GUI">" & @CRLF & _ " <Name>Another Test</Name>" & @CRLF & _ " <CommandLine>Examp2.EXE</CommandLine>" & @CRLF & _ " <Input>Test Input</Input>" & @CRLF & _ " <Output>10</Output>" & @CRLF & _ " </Test>" & @CRLF & _ " <Test/>" & @CRLF & _ " <Test />" & @CRLF & _ " <Test></Test>" & @CRLF & _ " <Test attribute = "value" attribute2="value2"/>" & @CRLF & _ " <Test attribute = "value" attribute2="value2" />" & @CRLF & _ " <Test attribute = "value" attribute2="value2" ></Test>" & @CRLF & _ "" & @CRLF & _ "" & @CRLF & _ "" & @CRLF & _ "<([^\/> ]+?)\s*?([^>]*)\s*(?:\/>|>(.*)<\/\1>) - (with g-, s- & U-modifiers) finds all tags in scope" & @CRLF & _ "" & @CRLF & _ "1st group is tagname" & @CRLF & _ "2nd group is attributes" & @CRLF & _ "3rd group (if it exists) is value of the tag" & @CRLF & _ "" & @CRLF & _ "Apply pattern again on 3th group to find internal tags (recurse in the code to parse entire xml!)" & @CRLF & _ "" & @CRLF & _ "" & @CRLF & _ "Apply pattern below on 2nd group to find all attributes:" & @CRLF & _ "" & @CRLF & _ "\s*([^<>\=" ]+)\s*=\s*"([^"]*)" - (with g-modifier) finds attributes" & @CRLF & _ "" & @CRLF & _ " 1st group is attributename" & @CRLF & _ " 2nd group is attributevalue" Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYGLOBALFULLMATCH) Local $aFullArray[0] For $i = 0 To UBound($aArray) -1 _ArrayConcatenate($aFullArray, $aArray[$i]) Next $aArray = $aFullArray ; Present the entire match result _ArrayDisplay($aArray, "Result")

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 AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm