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
Processing...

Test String

Code Generator

Language

Generated Code

import re regex = re.compile(r""" (?<= \s ) # Match opening braket (i.e., `[`). ( \[ ) # Match any single character (e.g., `x`). ( . ) # Matching closing braket (i.e., `]`) ( \] ) (?= \s* [?!*]? \s* ) # Exclude entries without text (i.e., incl. in tables). (?! \s* [?!*]? \s* \| | \s* [?!*]? \s* $ ) # Match the text (i.e., capture based on modifier presence). (?: # Match modifier (i.e., `!`, `?`, or `*`) and the text that follows. \s* ( [!?*] ) \s* ( .*? ) | # Match the text that does not follow a modifier. \s* (?! [!?*]) \s* ( .*? ) ) # Match until either of the stops that follow are met. (?= \s+ \^[a-z0-9]{6,} | \s+ \| | \s*$) """, flags=re.MULTILINE | re.VERBOSE) test_str = ("# Should match\n\n" "- [ ] Some task\n" "- [ ] Some task | [[link]]\n" "- [ ] Some task ^abcdef\n" "- [ ] Some task | [[link]] ^abcdef\n" "- [ ] ! Some task\n" "- [ ] ! Some task | [[link]]\n" "- [ ] ! Some task ^abcdef\n" "- [ ] ! Some task | [[link]] ^abcdef\n" "- [ ] Task one | [ ] ! Task two | [ ] Task three ^abcdef\n\n" "| Tracker | Task | Backlog |\n" "| ----------: | :---------------------- | :------- |\n" "| 00:00-00:00 | [ ] Task item | [[linK]] |\n" "| 00:00-00:00 | [ ] Task item ^abcdef | [[link]] |\n" "| 00:00-00:00 | [ ] [[task-item]] | [[link]] |\n" "| 00:00-00:00 | [ ] ! Task item | [[linK]] |\n" "| 00:00-00:00 | [ ] ! Task item ^abcdef | [[link]] |\n" "| 00:00-00:00 | [ ] ! [[task-item]] | [[link]] |\n\n" "# Should not match\n\n" "- [ ] \n" "- [ ]\n" "- [ ] \n" "- [ ] ! \n" "- [ ] !\n" "- [ ] ! \n\n" "| Tracker | Task | Backlog |\n" "| ----------: | :---------------------- | :------- |\n" "| 00:00-00:00 | [ ] | [[linK]] |\n" "| 00:00-00:00 | [ ] ! | [[linK]] |\n\n" "# Desired outcome\n\n" "- group `notation`:\n" " - match: `[` and `]`\n\n" "- group `symbol`: \n" " - match: any single character (e.g., `\\s`) between `[` and `]`\n\n" "- group `modifier`:\n" " - match: `!`, `?`, or `*` that follows after `[ ]`\n\n" "- group `text`: \n" " - match: task text after `[ ]` without modifier present\n\n" "- group `textmod`: \n" " - match: task text after `[ ] !` with modifier present\n") matches = regex.finditer(test_str) for match_num, match in enumerate(matches, start=1): print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}") for group_num, group in enumerate(match.groups(), start=1): print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")

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