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

r"
"

Test String

Code Generator

Language

Generated Code

const regex = new RegExp('([\\.\\w\\?]+)\\s+([\\dABCDEF]+) - ([\\dABCDEF]+)\\s+([\\dABCDEF]+)', '') const str = `.noinit 00001000 - 00001012 13 DATA (1 bytes space 00001013 - 00001013) .ramcode 00001014 - 000017CB 7B8 DATA .bss 000017CC - 00002A6A 129F DATA (1 bytes space 00002A6B - 00002A6B) .data 00002A6C - 00002B35 CA DATA WARNING: Non-dotted segment name DSPSEGMENT2.DRIVER120 DSPSEGMENT2.DRIVER120 00002B36 - 00002B3D 8 DATA .ISOBUFFERS 00002B3E - 00002CBD 180 DATA .uart 00002CBE - 00002DBD 100 DATA (562 bytes space 00002DBE - 00002FEF) .qspidata 00002FF0 - 00002FFF 10 DATA .icache 00003000 - 00003FFF 1000 DATA (20480 bytes space 00004000 - 00008FFF) .rsstack0 00009000 - 000092FF 300 DATA .rsmails0 00009300 - 000096FF 400 DATA .trace 00009700 - 000098FF 200 DATA `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; if ((m = regex.exec(str)) !== null) { // 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