re模块的结果小练习题

1.匹配标签

 import re
 ret = re.search('<(?P<tag_name>\w+)>\w+</(?P=tag_name)>','<h1>hello</h1>')
 #还可以在分组中利用?P<name>的形式给分组起名字
 #获取的匹配结果可以直接用group('名字')拿到对应的值
 print(ret.group())
 print(ret.group('tag_name'))

 # -------------------------
 ret = re.search(r'<(\w+)>\w+</\1>','<h1>hello</h1>')
 #如果不给分组起名字，也可以用\序号来找到对应的组，表说要找的内容和前面的组的内容一致
 #获取的匹配结果可以直接用group(序号)拿到对应的值
 print(ret.group())
 print(ret.group(1))

匹配标签

2.匹配整数

 import re
 ret = re.findall(r'\d+',"1-2*(60+(-40.35/5)-(-4*3))")
 print(ret)

 import re
 ret = re.findall(r'-?\d+\.\d*|(-?\d+)',"1-2*(60+(-40.35/5)-(-4*3))")
 print(ret)

 ret.remove('')
 print(ret)

数字匹配

3.数字匹配

 # 3.数字匹配
 # 1.匹配一段文本中的每行的时间字符串，比如’1990-07-12‘

 # 1.分别取出一年的十二个月：
 while True:
     cmd = input('请输入月份：>>')
     if re.match(r'^(0?[1-9]|1[0-2])$',cmd):
         print('格式正确')
     else:
         print('格式错误')

 # 2.
 ret =re.match(r'^(0?[1-9]|1[0-2])$','')
 print(ret.group())

 # 一个月的31天
 ret = re.match(r'^((0?[1-9])|((1|2)[0-9])|30|31)$','')#从头匹配
 print(ret.group())

 # 匹配QQ号
 while True:
     cmd = input('请输入你扣扣号：>>')
     if re.match(r'^[1-9][0-9]{4,10}$',cmd):
         print('输入正确')
     else:
         print('输入错误')

 # 浮点数
 ret = re.match(r'-?\d+\.?\d*','21.5')
 print(ret.group())

数字匹配

4.爬虫练习

 import requests

 import re
 import json

 def getPage(url):

     response=requests.get(url)
     return response.text

 def parsePage(s):

     com=re.compile('<div class="item">.*?<div class="pic">.*?<em .*?>(?P<id>\d+).*?<span class="title">(?P<title>.*?)</span>'
                    '.*?<span class="rating_num" .*?>(?P<rating_num>.*?)</span>.*?<span>(?P<comment_num>.*?)评价</span>',re.S)

     ret=com.finditer(s)
     for i in ret:
         yield {
             "id":i.group("id"),
             "title":i.group("title"),
             "rating_num":i.group("rating_num"),
             "comment_num":i.group("comment_num"),
         }

 def main(num):

     url='https://movie.douban.com/top250?start=%s&filter='%num
     response_html=getPage(url)
     ret=parsePage(response_html)
     print(ret)
     f=open("move_info7","a",encoding="utf8")

     for obj in ret:
         print(obj)
         data=json.dumps(obj,ensure_ascii=False)
         f.write(data+"\n")

 if __name__ == '__main__':
     count=0
     for i in range(10):
         main(count)
         count+=25