Regular + simple reptiles

1. Regular

   ---

   '''
   只要使用量词：* + ？ {}  贪婪模式
   *?  +? ?? {}?  非贪婪模式
   
   贪婪模式：正则表达式一般趋向于最大长度匹配，也就是所谓的贪婪匹配。如上面使用模式pattern 匹配字符串example，
   匹配到的结果就是”abbbbbb”整个字符串。
   
   非贪婪模式：在整个表达式匹配成功的前提下，尽可能少的匹配。
   如上面使用模式pattern 匹配字符串example，匹配到的结果就只是”ab”整个字符串。
   '''
   import re
   
   s = 'abbbbbHello'
   result = re.match(r'ab+?', s)
   print(result.group())
   
   # 分组引用： \number ,  ?P<名>  ?P=名
   
   s = '<div><a href="http://www.baidu.com">百度</a></div>123'
   #
   # result = re.match(r'<(.+)><(.+) href="(.+?)">(.+?)</\2></\1>', s)
   # print(result.group(1))
   # print(result.group(2))
   # print(result.group(3))
   # print(result.group(4))
   
   print('————————————————————————————————————')
   
   result = re.match(r'<(?P<e1>.+)><(?P<e2>.+) href="(.+?)">(.+?)</(?P=e2)></(?P=e1)>(\d+)', s)
   print(result)
   print(result.group(1))
   print(result.group(2))
   print(result.group(3))
   print(result.group(4))
   print(result.group(5)) #(?P=e2)  (?P=e1)  不算分组
   
   

    

2. Simple reptiles

   ---

   '''
   正则表达式 + 爬虫
   
   requests 就是一个浏览器
   User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36
   '''
   # import re
   #
   # import requests
   
   # url = 'https://imgsa.baidu.com/forum/w%3D223/sign=7c297b08b00e7bec23da04e31c2eb9fa/e433434a20a446234cdfca659022720e0cf3d7b5.jpg'
   # response = requests.get(url, headers={
   #     'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36'})
   # # code = response.status_code
   # # print(code)
   # content = response.content
   #
   # with open('images/a1.jpg', 'wb') as ws:
   #     ws.write(content)
   #
   # print('下载完毕')
   # import os
   # import re
   #
   # ele = '''
   # <img src="https://imgsa.baidu.com/forum/w%3D223/sign=7c297b08b00e7bec23da04e31c2eb9fa/e433434a20a446234cdfca659022720e0cf3d7b5.jpg" style="width:223px;height:278px;left:0px;top:0px;">
   # <img src="https://imgsa.baidu.com/forum/w%3D223/sign=a3f5fb73a5345982c58ae2903ff4310b/de3d1ddfa9ec8a13570f38e7ff03918fa0ecc0b5.jpg" style="width:223px;height:315px;left:0px;top:0px;">
   # <img src="http://tiebapic.baidu.com/forum/wh%3D90%2C99%3Bcrop%3D0%2C0%2C90%2C90/sign=6a0c52c1c33f8794d3aa4027e23737cd/fdfaaf51f3deb48f741d10a7e71f3a292df57857.jpg" attr="45157" data-original="http://tiebapic.baidu.com/forum/wh%3D90%2C99%3Bcrop%3D0%2C0%2C90%2C90/sign=6a0c52c1c33f8794d3aa4027e23737cd/fdfaaf51f3deb48f741d10a7e71f3a292df57857.jpg" bpic="http://tiebapic.baidu.com/forum/pic/item/fdfaaf51f3deb48f741d10a7e71f3a292df57857.jpg" class="threadlist_pic j_m_pic " style="display: inline; width: 89px; height: 90px;">
   # <img src="https://imgsa.baidu.com/forum/wh%3D135%2C90/sign=3a8846c3023387449c90277d623af5c0/659b033b5bb5c9ead9621b70db39b6003bf3b394.jpg" attr="7854" data-original="https://imgsa.baidu.com/forum/wh%3D135%2C90/sign=3a8846c3023387449c90277d623af5c0/659b033b5bb5c9ead9621b70db39b6003bf3b394.jpg" bpic="https://imgsa.baidu.com/forum/pic/item/659b033b5bb5c9ead9621b70db39b6003bf3b394.jpg" class="threadlist_pic j_m_pic " style="display: inline; width: 135px; height: 90px;">
   # '''
   #
   # image_list = re.findall(r'<img src="(.+?)"', ele)
   # # print(image_list)
   #
   # for image in image_list:
   #     # 使用requests模拟浏览器获取内容，image就是图片的连接地址
   #     response = requests.get(image, headers={
   #         'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36'})
   #
   #     content = response.content
   #     filename = os.path.split(image)[1]
   #     # 本地保存
   #     with open('images/' + filename, 'wb') as ws:
   #         ws.write(content)
   #
   #     print('{}下载完成'.format(filename))
   import os
   import re
   
   import requests
   
   ele = '''
   http://n.sinaimg.cn/sinacn17/213/w1680h933/20180710/0273-hezpzwu8730048.jpg
   https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1578368718950&di=99e6f9921699450fe2da48e4ae90c51b&imgtype=0&src=http%3A%2F%2Fp2.qhimgs4.com%2Ft0128307802c64fd817.jpg
   http://img0.imgtn.bdimg.com/it/u=4250364844,2026637142&fm=26&gp=0.jpg
   '''
   
   imagelist = re.findall('(http://.+?jpg)', ele)
   print(imagelist)
   for image in imagelist:
       response = requests.get(image, headers={
           'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36'})
       context = response.content
       finame = os.path.split(image)[1]
       with open('images/' + finame, 'wb') as ws:
           ws.write(context)