正则
- 功能：模糊匹配（针对字符串操作）
- re由c语言编写，效率也会快很多
- .可以指代任意字符除了换行符
- ^开头开始匹配
- $结尾匹配
- *匹配0到无穷次
- +代匹配1到无穷次
- ？匹配0或者1次
- {}自定义匹配
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import re print(re.findall("alex*","464ale") ) #['ale'] print(re.findall("alex+","464ale") ) #[] print(re.findall("alex?","5646alex") )#['alex'] print(re.findall("alex{3,5}","asdasdalexxx") )#['alexxx']
print(re.findall("alex{3,5}?","asdasdalexxxxx") ) ？可以改成惰性匹配 - []或者，字符集中只有^/-有特殊意义(^在字符集中表示非)
print(re.findall("a[a-z]*","hiahdsih") ) #['ahdsih']
print(re.findall("\([^()]*\)","1515+565*565(556*54644)") ) #['(556*54644)']
- \d是数字0到9，相当于[0,9]
- \D非数字字符
- \s任何空白字符
- \S任何非空白字符
- \w任何数字字母字符
- \W非任何数字字母字符
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print(re.findall("\d","sadsasdasd12") ) #['1', '2'] print(re.findall("\d+","sadasd54654") ) #['54654']
- \d任何特殊字符
print(re.findall("i\\b","hello i am aia") ) print(re.findall("e\\\\","he\l") ) #['e\\'] print(re.findall(r"e\\","he\l") ) #['e\\']
- |
print(re.findall(r"ka|b","hsaudhka|b") )#['ka', 'b'] print(re.findall(r"ka|bc","hsaudhka|b") )#['ka'] print(re.findall(r"ka|bc","hsaudhka|bc") )#['ka', 'bc']
print(re.search("(?P<name>[a-z]+)\d+","alex36wusir34").group() ) print(re.search("(?P<name>[a-z]+)\d+","alex36wusir34").group("name") )
- findall把匹配结果放在列表中
- search方法智能匹配出一个结果并且需要group来调用
- match同search，只不过只能从开头取
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print(re.split("[ab]","abc") ) #按a分完后按b分
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print(re.sub("\d","A","saljdl6545645")，4 ) #saljdlAAAAAAA 4代表匹配次数 subn('saljdlAAAAAAA', 7)
- comlile
com =re. compile("\d+") print(com.findall("sauhdy54564")) #['54564'] 方便重复使用
- finditer
print(re.finditer("\d","sads4s5")) #迭代器
- 分组
print(re.findall("www.(baidu).com","jiiojijwww.baidu.com") ) #['baidu'] print(re.findall("www.(?:baidu).com","jiiojijwww.baidu.com") )#['www.baidu.com']
