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

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"^\[Error: +(?<source_path>(?<file>[^\s\n](?:[^\n:\\]+|\\.)+?)(?::(?<line>\d+)(?::(?<column>\d+)))?) *$" test_str = ("/usr/local/lib/node_modules/stylus/bin/stylus:685\n" " throw err;\n" " ^\n\n" "[Error: /Users/user/path/to/stylus/file/invalid.styl:34:5\n" " 30| ==/UserStyle== */\n" " 31| \n" " 32| @-moz-document regexp(\"https?://(www\\\\.)?typescriptlang.org/(v2/)?docs.*$\"),\n" " 33| regexp(\"https?://(www\\\\.)?(staging-)?typescript\\\\.org/docs/.*$\")\n" " 34| error(\"compile error\")\n" "-----------^\n" " 35| \n\n" "compile error\n" "] {\n" " fromStylus: true,\n" " lineno: 34,\n" " column: 5,\n" " filename: '/Users/disk0/git.local/stylus-stylus/static/test/testFiles/invalid.styl',\n" " stylusStack: '',\n" " input: '/* ==UserStyle==\\n' +\n" " '@name TypeScript Docs\\n' +\n" " '@description Expands width of code blocks and moves navigation bar fully to the left\\n' +\n" " '@version 0.0.12\\n' +\n" " '@namespace github.com/disk0/stylus/typescript.org/docs\\n' +\n" " '\\n' +\n" " '@author disk0 (github.com/disco0)\\n' +\n" " '@license MIT\\n' +\n" " '\\n' +\n" " '@preprocessor stylus\\n' +\n" " '\\n' +\n" " '@var select CodeFont \"Font for code displayed on page.\" [\\n' +\n" " ' \"Iosevka Extended*\",\\n' +\n" " ' \"Iosevka Expanded\",\\n' +\n" " ' \"Iosevka Term\",\\n' +\n" " ' \"Iosevka\",\\n' +\n" " '\\n' +\n" " ' \"SemanticHaskell\",\\n' +\n" " ' \"SemanticJavascript\",\\n' +\n" " ' \"SemanticCode\",\\n' +\n" " ' \"Hasklig\",\\n' +\n" " '\\n' +\n" " ' \"PragmataPro Mono Liga\",\\n' +\n" " '\\n' +\n" " ' \"monospace\"\\n' +\n" " ']\\n' +\n" " '@var number CodeFontSize \"Size of code in documentation\" [ 14, 1, 500, 1, \"px\" ]\\n' +\n" " '@var number CodeFontWeight \"Code font weight\" [ 400, 100, 900, 100 ]\\n' +\n" " '@var number DocTextWidth \"Width of text content in documentation\" [ 1000, 300, 5000, 100, \"px\" ]\\n' +\n" " '==/UserStyle== */\\n' +\n" " '\\n' +\n" " '@-moz-document regexp(\"https?://(www\\\\\\\\.)?typescriptlang.org/(v2/)?docs.*$\"),\\n' +\n" " '\\t regexp(\"https?://(www\\\\\\\\.)?(staging-)?typescript\\\\\\\\.org/docs/.*$\")\\n' +\n" " ' error(\"compile error\")\\n'\n" "}\n") matches = re.finditer(regex, test_str, re.MULTILINE) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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 Python, please visit: https://docs.python.org/3/library/re.html