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

Substitution
Processing...

Code Generator

Language

Generated Code

import re regex = re.compile((r"(?sx) # Free-Spacing\n" r"(?(DEFINE) # Define a few subroutines\n" r" (?<double>&ldquo;(?:(?!&[lr]squo;).)*&rdquo;) # full set of doubles (no quotes inside)\n" r" (?<single>&lsquo;(?:(?!&[lr]dquo;).)*&rsquo;) # full set of singles (no quotes inside)\n" r" (?<notquotes>(?:(?!&[lr][sd]quo;).)*) # chars that are not quotes\n" r") # end DEFINE\n\n" r"^ # Start of string\n" r"(?: # Start non-capture group\n" r" (?&notquotes) # Any non-quote chars\n" r" &l(?<type>[sd])quo; # Opening quote, capture single or double type\n" r" # any full singles, doubles, not quotes or recursion\n" r" (?:(?&single)|(?&double)|(?&notquotes)|(?R))*\n" r" &r\k<type>quo; # Closing quote of the correct type\n" r")*+ # Repeat non-capture group\n" r"(?&notquotes)\n" r"\K\n" r"&[lr][sd]quo; # unmatched quote\n")) test_str = ("&ldquo;Full Quote&rdquo; The Left Quote is Missing&rdquo;\n") subst = "" result = regex.sub(subst, test_str, count=1) if result: print(result)

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