python3----scrapy(笔记)

 import scrapy
 import sys
 # import io
 # sys.stdout = io.TextIOWrapper(sys.stdout.buffer, encoding='gb18303')
 from scrapy.selector import Selector, HtmlXPathSelector
 class ChoutiSpider(scrapy.Spider):
     name = 'chouti'
     # allowed_domains = ['chouti.com']
     start_urls = ['http://dig.chouti.com/']

     def parse(self, response):
         # print(response.text)
         # content = str(response.body, encoding='utf-8')
         # print(content)
         # hxs = Selector(response=response).xpath('//a').extract()
         # for i in hxs:
         #     print(i)
         # hxs = Selector(response=response).xpath('//div[@id="content-list"]/div[@class="item"]').extract()
         # for i in hxs:
         #     print(i)
         hxs = Selector(response=response).xpath('//div[@id="content-list"]/div[@class="item"]')   # 标签对像列表
         for obj in hxs:
             a = obj.xpath('.//a[@class="show-content color-chag"]/text()').extract_first()
             print(a.strip())

 '''
 //   表示子孙中
 .//  当前对像的子孙中
 /    儿子
 /div 儿子中的div标签
 /div[@id="i1"  儿子中的div标签且id=i1
 obj.extract()    列表中的每一个对象转换成字符串 =>[]
 obj.extract_first() 列表中的每一个对象转换成字符串=>列表第一个元素
 //div/text()   获取某个标签的文本