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
No Match

r"
"
gm

Test String

Substitution

Processing...

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\s]+\s\s).*" test_str = ("0000000: 01010000 01001011 00000011 00000100 00010100 00000011 PK.... \n" "0000006: 00000000 00000000 00001000 00000000 01000000 10001101 ....@. \n" "000000c: 00101001 01000110 10011111 00101100 00000001 11100100 )F.,.. \n" "0000012: 01111100 00101011 00000000 00000000 10111110 11010111 |+.... \n" "0000018: 00000010 00000000 00001101 00000000 00000000 00000000 ...... \n" "000001e: 01110000 01100001 01101110 01100100 01100001 01011111 panda_ \n" "0000024: 01100010 01101001 01101110 00101110 01110100 01111000 bin.tx \n" "000002a: 01110100 10101100 10011010 01001001 10101110 10011011 t..I.. \n" "0000030: 01010000 00010000 01000101 11100111 01011001 10000101 P.E.Y. ") subst = "$1\\n" # You can manually specify the number of replacements by changing the 4th argument result = re.sub(regex, subst, test_str, 0, re.MULTILINE) if result: print (result) # 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