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

~
~
g

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"\[#](.*?)\)" test_str = ("# [#](http://heavy_code_industry.gitee.io/code_heavy_industry/pro002-maven/chapter05/#第五章-其他核心概念)第五章 其他核心概念\n\n" "## [#](http://heavy_code_industry.gitee.io/code_heavy_industry/pro002-maven/chapter05/#_1、生命周期)1、生命周期\n\n" "### [#](http://heavy_code_industry.gitee.io/code_heavy_industry/pro002-maven/chapter05/#_1作用)①作用\n\n" "为了让构建过程自动化完成，Maven 设定了三个生命周期，生命周期中的每一个环节对应构建过程中的一个操作。\n\n" "### [#](http://heavy_code_industry.gitee.io/code_heavy_industry/pro002-maven/chapter05/#_2三个生命周期)②pile 编译测试源代码。 process-test-classes test 使用合适的单元测试框架运行测试。这些测试代码不会被打包或部署。 prepare-package package 接受编译好的代码，打包成可发布的格式，如JAR。 pre-integration-test integration-test post-integration-test verify install将包安装至本地仓库，以让其它项目依赖。 deploy将最终的包复制到远程的仓库，以让其它开发人员共享；或者部署到服务器上运行（需借助插件，例如：cargo）。 |\n\n" "### [#](http://heavy_code_industry.gitee.io/code_heavy_industry/pro002-maven/chapter05/#_3特点)③特点\n\n" "- 前面三个生命周期彼此是独立的。\n" "- 在任何一个生命周期内部，执行任何一个具体环节的操作，都是从本周期最初的位置开始执行，直到指定的地方。（本节记住这句话就行了，其他的都不需要记）\n\n" "Maven 之所以这么设计其实就是为了提高构建过程的自动化程度：让使用者只关心最终要干的即可，过程中的各个环节是自动执行的。\n\n" "## [#](http://heavy_code_industry.gitee.io/code_heavy_industry/pro002-maven/chapter05/#_2、插件和目标)2、插件和目标\n\n" "### [#](http://heavy_code_industry.gitee.io/code_heavy_industry/pro002-maven/chapter05/#_1插件)①插件\n") matches = re.finditer(regex, test_str) 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