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

Substitution
Processing...

Code Generator

Language

Generated Code

import re regex = re.compile(r"((?:\"[^\"]*)\s*\")|((?:\'[^']*)\s*\')|((?:\`[^`]*)\s*\`)|((?:\b|\s)(?:const|function|let)\s)|(?:\/\/.*$)|(?:\/\*+(?:.|\s)*\*\/)|\s*", flags=re.IGNORECASE | re.MULTILINE) test_str = ("function myFunction() {\n" " let carName = \"Volvo\";\n" " // code here CAN use carName\n" "const test = 'string with \"quoted substring\"'; let airplane = 'fly'\n" "(\"and another string th'' as' asd 'ere\")\n" "labelForStrings: {\n" " `t'is a \"string\"`\n" " }\n" "}\n" "/*asd *****\n" "* 324 @*l;;?\\\\\\\n" "* multiline comment \n\n\n" "*** /\n" "*/") subst = "$1$2$3$4" result = regex.sub(subst, test_str) 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