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]
  • Character class intersection
    [\w&&[^\d]]
  • 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"^(\+ *|- *)?((?!0+)\d*?|(?!0{2,})\d*?\.(?!0+)\d*?)('|\")$|^(\+ *|- *)? *(?!0+)\d+?' *-? *(\d+?|\d*?\.\d*?)\"$|^((\+ *|- *)?((?!0+)|0 )\d*? *(?!0+)\d+?\/(?!0+)\d+?('|\"))$", flags=re.MULTILINE) test_str = (" - \n" " + \n" "- x 20'-4\"\n" "+ 20'\n" "- 20'\n" "20'3\"\n" "20'-3\"\n" "20' - 40\"\n" "-20'-20\"\n" "20'00\"\n" "20.45\"\n" "20.45'\n" "00.45'\n" "00.45\"\n" "00\"\n" "00'\n" "+20' - 0.45\"\n" " 20' - .45\"\n" ".20'-4\"\n" "0.30'-4\"\n" " 20'\n" "20'P\n" " 20\"\n" "20\"P\n" "0.20'\n" ".20'\n" "a'\n" "b\"\n" "- 20 1/2'\n" "+ 20 22/128\"\n" "20 0/2\"\n" "20 00/12'\n" "-1/2\"\n" "+ 1/2'\n" "0/2\"\n" "00/22\"\n" "+ 01/2\"\n" "23 00/30'\n" "23 12/03'\n" "23 02/20\"\n" "0 2/3'\n" "00 2/3'\n" "- 11 2/3'\n" "2 22'\n" "2 22/03'\n" "2 3/2\n" "23 00/30\n" "23 12/03\n" "23 02/20\n" "23/34\"\n" "23/23.4\"\n" "asf sf\"\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