Regular Expressions 101

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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

/
/
gm

Test String

Code Generator

Language

Generated Code

const regex = /\"apps\"\s+{\s+(\"(\d+)\"\s+\"\d+\"\s+)+\s+}/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('\\"apps\\"\\s+{\\s+(\\"(\\d+)\\"\\s+\\"\\d+\\"\\s+)+\\s+}', 'gm') const str = `"libraryfolders" { "0" { "path" "C:\\\\Program Files (x86)\\\\Steam" "label" "" "contentid" "-4617057559629097284" "totalsize" "0" "update_clean_bytes_tally" "26071119336" "time_last_update_corruption" "0" "apps" { "228980" "419015490" "250820" "5600094877" "705900" "2514926917" } } "1" { "path" "N:\\\\SteamLibrary" "label" "" "contentid" "3764071818320917735" "totalsize" "1000186310656" "update_clean_bytes_tally" "225615218162" "time_last_update_corruption" "0" "apps" { "221680" "7000427217" "223750" "221071349004" "223850" "3121585480" "236390" "45325788243" "348250" "2996347031" "438100" "832697714" "450390" "16625763869" "546560" "72900756522" "578080" "35943596276" "667970" "2603561151" "690790" "117594033997" "1118240" "2213415708" "1174180" "128249349313" "1250410" "1865648550" "1255560" "9741578437" "1517290" "66609320436" } } } `; // 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