Python正则表达式re.search()用法详解

import re
 
s = "Long live the people's Republic of China"
ret = re.search("^Long.*China$", s)
 
print(ret)
print(ret.group())
print(ret[0])

import re
 
s = "Long live the people's Republic of China"
ret = re.search("\s", s)
 
print(ret)
print(ret.start())

import re
 
s = "Long live the people's Republic of China"
ret = re.search("USA", s)
 
print(ret)

import re
 
s = "Long live the people's Republic of China"
# ret1 = re.search('long', s)  这行代码直接报错
ret1 = re.search('l', s)
print(ret1)
print(ret1.span())
print(ret1.string)
print(ret1.group())
 
print("*" * 50)
 
ret2 = re.search('long', s, re.I)
print(ret2)
print(ret2.span())
print(ret2.string)
print(ret2.group())

import re
 
s = 'abc123def456ghi789'
ret_compile = re.compile("([a-z]*)([0-9]*)([a-z]*)")
print(ret_compile)
 
ret = ret_compile.search(s)
print(ret)
print(ret.group())
print(ret.group(0))  # group()和group(0) 一样匹配的是整体
print(ret.group(1))  # 匹配第1个小括号的内容
print(ret.group(2))  # 匹配第2个小括号的内容
print(ret.group(3))  # 匹配第3个小括号的内容

import re
 
s = 'abc123def456ghi789'
ret_compile = re.compile("(?P<num1>[a-z]*)(?P<num2>[0-9]*)(?P<num3>[a-z]*)")
print(ret_compile)
 
ret = ret_compile.search(s)
print(ret)
print(ret.group())
print(ret.group(0))  # group()和group(0) 一样匹配的是整体
print(ret.group(1))  # 匹配第1个小括号的内容
print(ret.group(2))  # 匹配第2个小括号的内容
print(ret.group(3))  # 匹配第3个小括号的内容
 
print("*" * 100)
 
print(ret.group())
print(ret.group("num1"))  # 这里效果等同于group(1)
print(ret.group("num2"))  # 这里效果等同于group(3)
print(ret.group("num3"))  # 这里效果等同于group(3)

import re

html='''<div id="songs-list">
    <h2 class="title">经典老歌</h2>
    <p class="introduction">
        经典老歌列表
    </p>
    <ul id ="list" class="list-group">
        <li data-view="2">一路上有你</li>
        <li data-view="7">
            <a href="/2.mp3" singer="任贤齐">沧海一声笑</a>
        </li>
        <li data-view="4" class="active">
            <a href="/3.mp3" singer="齐秦">往事随风</a>
        </li>
        <li data-view="6"><a href="/4.mp3" singer="beyond">光辉岁月</a></li>
        <li data-view="5"><a href="/5.mp3" singer="陈惠琳">记事本</a></li>
        <li data-view="5">
            <a href="/6.mp3" singer="邓丽君"><i class="fa fa-user"></i>但愿人长久</a>
        </li>
    </ul>
</div>
'''

result = re.search('<li.*?active.*?singer="(.*?)">(.*?)</a>',html,re.S)#re.S确保.能匹配到换行符
if result:
    print(result.group(1),result.group(2))

result = re.search('<li.*?singer="(.*?)">(.*?)</a>',html,re.S)
if result:
    print(result.group(1),result.group(2))