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"(### EXAMPLE ([0-9|[0-9]+))\n(```\n(```|```ps|```posh|```powershell)\n```\n)\n([\s\S]*?)\\`\\`\\`(\n\n|\n)([\s\S]*|\n)" test_str = ("### EXAMPLE 123\n" "```\n" "```powershell\n" "```\n\n" "$powershellVersion = '6 and lower'\n" "$description = 'custom code fencing example WITH markdown description'\n" "$names | Foreach-Object {} {\n" " write-host 'indentation is respected'\n" " Write-Host 'enormously long lines should not get cut off by our PlatyPS friends, ftw'\n" "}\n\n" "$emptyNewlinesInCode = $True\n" "\\`\\`\\`\n\n" "The description would continue after first closing code fence.\n\n" "This solution:\n\n" "- respects indentation\n" "- will treat description as markdown\n" "- seems close to what comes natural\n\n" "With this solution, the description itself could even contain code blocks:\n\n" "\\`\\`\\`js\n" "$var = docusaurus.New($config);\n" "\\`\\`\\`\n\n" "Pretty cool and the console becomes more readable too IMO, at least\n" "you now see where the code ends and the explanation begins\n\n" "\\`\\`\\`\n" "$unMonicked = \"should stay unmonicked, in other words powershell should not be added\"\n" " $indentationRespected = $True\n" "$theBadNews - \"that PlatyPS seems to cut off this line if a .\n" "is detected, wtf\"\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