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

/
/
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"^我?(想|要)?(到|去)?#都?有?((哪(儿|里)?|(啥|什么|哪些|啥子))((好|可)玩儿?的?(地(方|儿)?)?|好?地(方|儿))去?|(怎么|咋)玩儿?|(什么|啥|哪些)好?((旅游|游玩)?(景点|攻略)|风景区|旅游区))(吗|呢|不|吧|嘛|么|呀|没|啊|阿)?$" test_str = ("\n" "#怎么玩\n" "#有哪里好玩的\n" "#有哪里好玩\n" "#什么好玩的\n" "#哪儿好玩\n" "#什么好玩的地方\n" "#有什么好玩的\n" "#有哪好玩的\n" "#都有什么好玩的\n" "#有什么好地方\n" "#啥好玩的\n" "#有什么可玩的\n" "#有什么好玩的地\n" "#有啥可玩的\n" "#有哪好玩\n" "#什么景点\n" "#有什么好玩的呀\n" "#有什么好玩\n" "#有哪些好玩的\n" "#有哪里好玩的地方\n" "#有啥好玩的没\n" "#都有哪些好玩的\n" "#有什么风景区\n" "#有什么好景点\n" "#有什么好玩的阿\n" "#有哪里好玩呀\n" "#有什么好玩的地儿\n" "#有什么地方去\n" "#有什么好玩的没\n" "#有啥好玩的不\n" "#哪儿好玩儿\n" "#有什么可玩儿的\n" "#哪儿好玩呀\n" "#有啥好玩的地方\n" "#什么好玩的呀\n" "#有什么好玩的地方\n" "#有啥子好玩的\n" "#什么好玩儿的\n" "#都有什么景点\n" "去#有什么好玩的地方\n" "我想去#有什么好玩儿的\n" "去#有什么好玩的呀\n" "去#有什么好玩\n\n\n" "去#旅游怎么样\n" "去#玩什么\n" "去#玩\n" "去#玩怎么样\n" "#去哪里好玩\n" "#有什么玩的\n" "#有好玩的么\n" "#什么地方好玩\n" "#攻略有吗\n" "#好玩的地方有哪些\n\n" "去#的攻略\n" "#风景区\n" "去#旅游\n" "#周边游\n" "#游玩攻略\n\n\n" "#有什么可玩的\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