Regular Expressions 101

Save & Manage Regex

  • Current Version: 1
  • Save & Share
  • Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
Sponsors
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
Processing...

Test String

Code Generator

Language

Generated Code

const regex = new RegExp('(?=(^\\d\\s{3}(chr\\d)\\s{2}\\d+\\s+\\D+\\d+\\.\\d+\\s+\\w+(?=(?:(?:\\s+[01]/[01])*?\\s+1/1){3})(?:(?:(?:\\s+[01]/[01])*?\\s+0/0){3})(?:\\s+[01]/[01])*\\s(^\\d\\s{3}((chr\\d)\\s{2}\\d+\\s+\\D+\\d+\\.\\d+\\s+\\w+(?:\\s+[01]/[01])*\\s)){1,2}^\\d\\s{3}(chr\\d)\\s{2}\\d+\\s+\\D+\\d+\\.\\d+\\s+\\w+(?=(?:(?:\\s+[01]/[01])*?\\s+1/1){3})(?:(?:(?:\\s+[01]/[01])*?\\s+0/0){3})(?:\\s+[01]/[01])*\\s))|(^\\d\\s{3}(chr\\d)\\s{2}\\d+\\s+\\D+\\d+\\.\\d+\\s+\\w+(?=(?:(?:\\s+[01]/[01])*?\\s+1/1){3})(?:(?:(?:\\s+[01]/[01])*?\\s+0/0){3})(?:\\s+[01]/[01])*$)', 'gm') const str = `0 chr1 1152 NaN G A 1355.64 NaN 1/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 4 chr1 1331 NaN A C 4171.07 NaN 0/0 0/1 0/1 0/1 0/0 0/1 0/1 0/1 0/1 0/0 0/1 0/1 5 chr1 1349 NaN T C 11194.50 NaN 0/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 6 chr1 1401 NaN T G 10825.80 NaN 0/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 8 chr1 4045 NaN G T 1917.92 NaN 1/1 1/1 1/1 0/0 0/0 0/0 0/1 0/0 0/0 0/0 0/0 0/0 8 chr1 4045 NaN G T 1917.92 NaN 1/1 1/1 1/1 0/0 0/0 0/0 0/1 0/0 0/0 0/0 0/0 0/0 5 chr1 1349 NaN T C 11194.50 NaN 0/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 6 chr1 1401 NaN T G 10825.80 NaN 0/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 8 chr1 4045 NaN G T 1917.92 NaN 1/1 1/1 1/1 0/0 0/0 0/0 0/1 0/0 0/0 0/0 0/0 0/0 6 chr1 1401 NaN T G 10825.80 NaN 0/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 8 chr1 4045 NaN G T 1917.92 NaN 1/1 1/1 1/1 1/1 1/1 1/1 0/1 1/1 0/1 1/1 0/1 1/1 8 chr1 4045 NaN G T 1917.92 NaN 1/1 1/1 1/1 0/0 0/0 0/0 0/1 0/0 0/0 0/0 0/0 0/0 5 chr1 1349 NaN T C 11194.50 NaN 0/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 6 chr1 1401 NaN T G 10825.80 NaN 0/1 0/1 0/1 0/1 1/1 0/1 0/1 0/1 0/1 1/1 0/1 0/1 8 chr1 4045 NaN G T 1917.92 NaN 1/1 1/1 1/1 1/1 1/1 1/1 0/1 1/1 0/1 1/1 0/1 1/1 8 chr1 4045 NaN G T 1917.92 NaN 1/1 1/1 1/1 0/0 0/0 0/0 0/1 0/0 0/0 0/0 0/0 0/0`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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 JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions