Regular Expressions 101

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  • Unit Tests (25)

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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"
"
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"^(?:(?P<type>(?:feat)|(?:fix)|(?:docs)|(?:style)|(?:refactor)|(?:test)|(?:merge)|(?:chore))(?: \((?P<issue>.+)\))?: (?P<subject>[A-Z0-9].{0,48}(?!\.).?)\n?)(?:\n(?P<body>(?:.*\n?)+))*$" test_str = ("feat: Summarize changes in around 50 characters or less\n\n" "More detailed explanatory text, if necessary. Wrap it to about 72\n" "characters or so. In some contexts, the first line is treated as the\n" "subject of the commit and the rest of the text as the body. The\n" "blank line separating the summary from the body is critical (unless\n" "you omit the body entirely); various tools like `log`, `shortlog`\n" "and `rebase` can get confused if you run the two together.\n\n" "Explain the problem that this commit is solving. Focus on why you\n" "are making this change as opposed to how (the code explains that).\n" "Are there side effects or other unintuitive consequences of this\n" "change? Here's the place to explain them.\n\n" "Further paragraphs come after blank lines.\n\n" " - Bullet points are okay, too\n\n" " - Typically a hyphen or asterisk is used for the bullet, preceded\n" " by a single space, with blank lines in between, but conventions\n" " vary here\n\n" "If you use an issue tracker, put references to them at the bottom,\n" "like this:\n\n" "Resolves: #123\n" "See also: #456, #789") 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