Regular Expressions 101

Save & Share

  • Current Version: 3
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
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
Processing...

Test String

Substitution
Processing...

Code Generator

Language

Generated Code

import re regex = re.compile(r"^((?:[^+\n]*\+){7})\d{8}(?=\+(?:\d{8})?\+)", flags=re.MULTILINE) test_str = ("UNA:+,? '\n" "UNB+UNOC:3+000000000+000000000+20190801:1115+00001+DDMP190001'\n" "UNH+00001+BRKE:01+00+0'\n" "INV+ED Format 1+Brustkrebs+19880117+E000000001+20080702+++1+0'\n" "FAL+087897044+0000000++Trägername+000000000+0+20080702++1+++J+N+N+N+N+N+++0'\n" "INL+181095200+385762115+++0'\n" "BEE+20080702++++0'\n" "BAA+++J+J++++++J+++++++J++0'\n" "BBA++++++++J++++++J+J++++++J+++++J+++J+J++++++++J+0'\n" "BHP+J+++++J+++++J+++++0'\n" "BLA+++J+++++++++0'\n" "BFA++++++++++++J++0'\n" "BSA++J+++J+J+++0'\n" "BAT+20190801+0'\n" "DAT+20080702++++0'\n" "UNT+000014+00001'\n" "UNZ+00001+00001'\n\n") subst = "\\g<1>20200101" 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