New-Python-模块之re其他

1、search：与findall用法完全一致，不一样的地方在于search匹配一次就结束

print(re.search('alex','alex say hello alex').group())

alex
匹配的是一个对象，拿到这个值，需要调group

2、match：match代表从头匹配

print(re.match('alex','alex say hello alex').group())
print(re.match('alex',' alex say hello alex').group())

相当于：
print(re.search('^alex','alex say hello alex').group())

3、split

print(re.split(':','root:x:0:0:/root::/bin/bash'))

['root', 'x', '0', '0', '/root', '', '/bin/bash']

4、sub---替换

print(re.sub('alex','SB','alex say i have on telsa my name is alex',1))
print(re.subn('alex','SB','alex say i have on telsa my name is alex'))
#后面1意思是替换一次，默认全部替换；

#subn：可以显示替换了几次：

SB say i have on telsa my name is alex
('SB say i have on telsa my name is SB', 2)

print(re.sub(r'(\w+)(\W+)(\w+)(\W+)(\w+)',r'\5\2\3\4\1','alex-love: SB'))
print(re.sub(r'^al',r'AAAAAAAAA','alex-love: SB alex'))

SB-love: alex
AAAAAAAAAex-love: SB alex

5、正则表达式重用

print(re.findall('^alex','alex say hello alex'))
print(re.search('^alex','alex say hello alex'))

obj=re.compile(r'^alex')
print(obj.findall('alex say hello alex'))
print(obj.search('alex say hello alex').group())

6、补充：

print(re.findall(r'<.*?>.*?</.*?>','<h1>hello</h1>'))
print(re.findall(r'<(.*?)>.*?</(.*?)>','<h1>hello</h1>'))
print(re.findall(r'<(.*?)>.*?</(\1)>','<h1>hello</h1>'))
print(re.findall(r'<(?P<k>.*?)>.*?</(?P=k)>','<h1>hello</h1>'))

['<h1>hello</h1>']
[('h1', 'h1')]
[('h1', 'h1')]
['h1']

取所有
取分组
同上
取k

7、取数字

print(re.findall('\-?\d+\.?\d*',"1-12*(60+(-40.35/5)-(-4*3))"))

['1', '-12', '60', '-40.35', '5', '-4', '3']

print(re.findall('\-?\d+',"1-12*(60+(-40.35/5)-(-4*3))"))
print(re.findall('\-?\d+\.\d+',"1-12*(60+(-40.35/5)-(-4*3))"))

print(re.findall('\-?\d+\.\d+|(\-?\d+)',"1-12*(60+(-40.35/5)-(-4*3))"))   #只留下整数
print(re.findall('(\-?\d+\.\d+)|\-?\d+',"1-12*(60+(-40.35/5)-(-4*3))"))    #只留下小数

expression='1-2*((60+2*(-3-40.0/5)*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2))'

print(re.search(r'\(([-+*/]?\d+\.?\d*)+\)',expression).group())  #取第一个括号内容
print(eval(expression))   牛逼