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
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"^.{0,1}(陪我一起)?听?你?(再|快|先)?能?(给我)?唱?(啊|一?个|吧|出来|一?首)?歌?(给我听|来听听)?(吧|啊|哇|呗|呀)?((好(么|嘛|吗))|好不好|小万|亲爱的|这么难)?.{0,1}$" test_str = ("你先唱给我听好吗\n" "快唱啊\n" "快唱啊你\n\n" "你唱吧\n" "你唱一个\n" "唱一首吧亲爱的\n" "再唱一首\n" "你快唱吧\n" "你能唱出来吗\n" "唱出来\n" "唱一个给我听呗好不好\n" "快唱\n" "唱\n" "唱吧\n" "你唱啊\n" "唱一个嘛\n" "唱一个啊\n" "来听你唱歌\n" "再给我唱一首呗\n" "唱歌小万\n" "你唱首歌给我听呗\n" "陪我一起唱歌好吗\n" "听你唱歌这么难\n" "唱首歌来听听\n\n\n" "你唱歌好好听啊再给我唱一首呗\n\n" "我现在就很不开心你唱首歌给我听呗\n\n" "会不会唱歌，唱首歌来听听") 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