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

/
/
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"^(?:[0-9A-Fa-f]+\s+){1,4}" test_str = ("A92 6100 011E Bsr P6\n" "A96 43EE 003A Lea.L $3A(A6), A1\n" "A9A 6100 013E Bsr P8\n" "A9E 6608 BNE.B L90\n" "AA0 4E91 Jsr (A1)\n" "AA2 70F5 MoveQ.L #$-B, D0\n" "AA4 6100 010C Bsr P6\n" "AA8 43F8 0AD8 L90: Lea.L (SysResName), A1\n" "AAC 76FF MoveQ.L #$-1, D3\n" "AAE 6100 012C Bsr P9\n" "AB2 6600 0004 BNE L91\n" "AB6 4E91 Jsr (A1)\n" "AB8 21F8 02A6 02B2 L91: Move.L (SysZone), (RAMBase)\n" "ABE 700C MoveQ.L #$C, D0\n" "AC0 A722 _NewHandleSysClear\n" "AC2 21C8 0AEC Move.L A0, (AppParmHandle)\n" "AC6 A02C _InitApplZone\n" "AC8 A04F _RDrvrInstall\n" "ACA 2F05 Move.L D5, -(A7)") subst = "" # 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