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"^(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]), (25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9]), (25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]|[0-9])$", flags=re.MULTILINE) test_str = ("Min val is 0. Leading zeros don't \n" "match unless the value is 0.\n" "0, 0, 0\n" "00, 0, 0\n" "0, 0, 00\n\n" "Max numeric number is 255, anything \n" "larger than 255 will not match.\n" "255, 255, 255\n" "255, 255, 256\n\n" "4-Digit numbers will not match\n" "1, 11, 111\n" "11, 111, 1111\n\n" "dangling commas do not match\n" "45, 67, 89\n" "45, 67, 89,\n\n" "Obviously if a dangling comma doesn't \n" "match, neither will 4 numbers.\n" "1, 2, 3\n" "1, 2, 3, 4\n\n" "Two numbers do not match, and adding a space,\n" "or space & comma, doesn't match either.\n" "0, 1, 2\n" "0, 1\n" "0, 1,\n" "0, 1, \n\n" "Single numbers do not match; adding a space &/or\n" "comma, will not cause the single number to match.\n" "9, 9, 9\n" "9\n" "9,\n" "9, ") 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