Regular Expressions 101

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  • Unit Tests (21)

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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"^((((\d+,)+\d+|(\d+(\/|-|#)\d+)|\d+L?|\*(\/\d+)?|L(-\d+)?|\?|[A-Z]{3}(-[A-Z]{3})?) ?){5,7})|(@(annually|yearly|monthly|weekly|daily|hourly|reboot))|(@every (\d+(ns|us|µs|ms|s|m|h))+)$" test_str = ("# cron\n" "0 0 1 1 * 1\n" "0 0 1 1 * 1,2\n" "0 0 1 1 * 1,2,3\n" "0 0 1 * * 1/4\n" "0 0 * * 0 1-4\n" "0 0 * * * 2/4\n" "0 * * * * *\n\n" "# variations\n" "10 12 * * 1,2,3,4,5\n" "* 10 12 * * 1,2,3,4,5\n" "* */5 * * * *\n\n" "*/4 */4 */4 * * *\n\n" "# At 12:00 pm (noon) every day during the year 2017:\n" "0 0 12 * * ? 2017\n" "# Every 5 minutes starting at 1 pm and ending on 1:55 pm and then starting at 6 pm and ending at 6:55 pm, every day:\n" "0 0/5 13,18 * * ?\n" "# Every minute starting at 1 pm and ending on 1:05 pm, every day:\n" "0 0-5 13 * * ?\n" "# At 1:15 pm and 1:45 pm every Tuesday in the month of June:\n" "0 15,45 13 ? 6 Tue\n" "# At 9:30 am every Monday, Tuesday, Wednesday, Thursday, and Friday:\n" "0 30 9 ? * MON-FRI\n" "# At 9:30 am on 15th day of every month:\n" "0 30 9 15 * ?\n" "# At 6 pm on the last day of every month:\n" "0 0 18 L * ?\n" "# At 6 pm on the 3rd to last day of every month:\n" "0 0 18 L-3 * ?\n" "# At 10:30 am on the last Thursday of every month:\n" "0 30 10 ? * 5L\n" "# At 6 pm on the last Friday of every month during the years 2015, 2016 and 2017:\n" "0 0 18 ? * 6L 2015-2017\n" "# At 10 am on the third Monday of every month:\n" "0 0 10 ? * 2#3\n" "# At 12 am midnight on every day for five days starting on the 10th day of the month:\n" "0 0 0 10/5 * ?\n\n" "# more\n" "0 0 12 * * ?\n" "0 15 10 ? * *\n" "0 15 10 * * ?\n" "0 15 10 * * ? *\n" "0 15 10 * * ? 2005\n" "0 * 14 * * ?\n" "0 0/5 14 * * ?\n" "0 0/5 14,18 * * ?\n" "0 0-5 14 * * ?\n" "0 10,44 14 ? 3 WED\n" "0 15 10 ? * MON-FRI\n" "0 15 10 15 * ?\n" "0 15 10 ? * 6L\n" "0 15 10 ? * 6L 2002-2005\n" "0 15 10 ? * 6#3\n" "0 0 12 1/5 * ?\n" "0 11 11 11 11 ?\n\n" "# predefined\n" "@annually\n" "@yearly\n" "@monthly\n" "@weekly\n" "@daily\n" "@hourly\n" "@reboot\n\n" "# every\n" "@every 5s\n" "@every 20h30m\n\n" "#individual forms\n" "1,2,3\n" "1,2\n" "1/2\n" "1-2\n" "1\n" "*\n" "0\n" "*/4\n" "6#3\n" "L\n" "5L\n" "L-2\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