Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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

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'(?<!\S).(?!\S)' test_str = ("a interior Casquillo Dint.50 100\n" "brg aligning Self MM161Z end rod\n" "del eje4 Junta hendidura\n" "352 Junta tórica .20279\n" "2z/C3GJN Rodamiento\n" "pos. Ser. 440PM18002 Interruptor\n" "Reductor SR12013 LF de velocidad\n" "Sick M40Z025023TB1 fotoeléct. Barrera\n" "PR Acoplamiento SA00177\n" "cable 4p Conector micro 4m 889DF4AC5\n" "Brazo actuador 399 largo:\n" "Rodillo 114mm palanca morro largo:\n" "Rodillo 330180000 libre\n" "shaft bar 351819028 Nose\n" "lineal excel Nook Rodamiento\n" "Fotocélula Banner\n" "cable EL03926 Prox. Sensor\n" "EL99942 Ventilador\n" "Cilindro reparado HY00115 hidráulico\n" "SR10510 Reductor velocidad de\n" "barra largo Rodillo de 98mm morro\n" "Rueda horno nivel de centrado\n" "SENSOR:VIBRATION,IP68,500G RANGE,MAX165°\n" " | XSM-3034-30-PP iglidur X sleeve bearing\n" "KIT:HI-TECH,OK143521,O-RING 5/2 WAY,VLV a |\n") matches = re.finditer(regex, test_str, re.MULTILINE) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # 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