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慕课笔记--python原生爬虫“笔记”

慕课笔记--python原生爬虫“笔记”

作者: 敬楠 | 来源:发表于2018-10-08 10:51 被阅读25次

    之所以叫“笔记”,并非原创,只是总结。原创作者是慕课老师--七月,很喜欢他的课买了他很多课(打个广告)。仅供学习交流。

    爬虫分析

    熊猫tv.png

    ----需求:对一个直播网站的某个分类模块人气进行排名。

    ----分析:对图中红色区域“video-nickname”、“video-number”进行抓取和排序。

    ----代码实现:这里是对正则表达式的及python语法的一些考核。


    具体代码实现

    第一阶段:发起网络请求请求到所需分析的html页面

    # 引入网络框架
    from urllib import request
    
    
    class Spider:
        url = 'https://www.panda.tv/cate/lol?pdt=1.24.s1.3.4jhlkpnlco3'
    #第一阶段:发起网络请求请求到所需分析的html页面
        def __fetch_content(self):
    
            r = request.urlopen(Spider.url)
            html = r.read()
            html = str(html, encoding='utf-8')
            print(html)
    
        def run(self):
            self.__fetch_content()#第一阶段
    
    
    spider = Spider()
    spider.run()
    

    第二阶段:分析这个html页面,提取到我们所要关注的标签

    # 引入网络框架\正则框架
    from urllib import request
    import re
    
    
    class Spider:
        url = 'https://www.panda.tv/cate/lol?pdt=1.24.s1.3.4jhlkpnlco3'
        root_pattern = '<div class="video-info">([\s\S]*?)</div>'
        #第二阶段
        # \s 匹配空白字符,\S 匹配非空白字符 []字符集
        # *匹配*号前面的字符0次或跟多次 ?非贪婪 匹配到<d就结束了
    
        def __fetch_content(self):
    
            r = request.urlopen(Spider.url)
            html = r.read()
            html = str(html, encoding='utf-8')
            return html
    #第二阶段:分析这个html页面,提取到我们所要关注的标签
        def __analysis(self, html):
            root_html = re.findall(Spider.root_pattern, html)
            print(root_html[0])
    
        def run(self):
            html = self.__fetch_content()
            self.__analysis(html)
    
    
    spider = Spider()
    spider.run()
    

    获得到结果:


    获得所需.png

    第三阶段:获取“video-nickname”、“video-number”

    # 引入网络框架\正则框架
    from urllib import request
    import re
    
    
    class Spider:
        url = 'https://www.panda.tv/cate/lol?pdt=1.24.s1.3.4jhlkpnlco3'
        root_pattern = '<div class="video-info">([\s\S]*?)</div>'
        name_pattern = '</i>([\s\S]*?)</span>'
        # number_pattern = '<span class="video-number">15.1万</span>'
        number_pattern = '<span class="video-number">([\s\S]*?)</span>'
        # \s 匹配空白字符,\S 匹配非空白字符 []字符集
        # *匹配*号前面的字符0次或跟多次 ?非贪婪 匹配到<d就结束了
    
        def __fetch_content(self):
    
            r = request.urlopen(Spider.url)
            html = r.read()
            html = str(html, encoding='utf-8')
            return html
    
        def __analysis(self, html):
            root_html = re.findall(Spider.root_pattern, html)
            anchors = []
            for html in root_html:
                name = re.findall(Spider.name_pattern, html)
                number = re.findall(Spider.number_pattern, html)
                anchor = {"name" :name, "number":number }
                anchors.append(anchor)
            print(anchors[0])
    
        def run(self):
            html = self.__fetch_content()
            self.__analysis(html)
    
    
    spider = Spider()
    spider.run()
    

    结果
    {'name': ['\n 守卫者 ', '\n '], 'number': ['1.9万']}

    测试结果.png

    继续优化:将空格删除

        # 精炼我们的函数
        def __refine(self, anchors):
    
            express = lambda anchor: {
                'name': anchor['name'][0].strip(),
                'number': anchor['number'][0]
            }
            return map(express, anchors)
    
        def run(self):
            html = self.__fetch_content()
            anchors = self.__analysis(html)
            anchors = list(self.__refine(anchors))
            print(anchors)
    

    结果


    测试结果.png

    第四阶段 对抓取的数据进行排序

    # 引入网络框架\正则框架
    from urllib import request
    import re
    
    
    class Spider:
        url = 'https://www.panda.tv/cate/lol?pdt=1.24.s1.3.4jhlkpnlco3'
        root_pattern = '<div class="video-info">([\s\S]*?)</div>'
        name_pattern = '</i>([\s\S]*?)</span>'
        # number_pattern = '<span class="video-number">15.1万</span>'
        number_pattern = '<span class="video-number">([\s\S]*?)</span>'
        # \s 匹配空白字符,\S 匹配非空白字符 []字符集
        # *匹配*号前面的字符0次或跟多次 ?非贪婪 匹配到<d就结束了
    
        def __fetch_content(self):
    
            r = request.urlopen(Spider.url)
            html = r.read()
            html = str(html, encoding='utf-8')
            return html
    
        def __analysis(self, html):
            root_html = re.findall(Spider.root_pattern, html)
            anchors = []
            for html in root_html:
                name = re.findall(Spider.name_pattern, html)
                number = re.findall(Spider.number_pattern, html)
                anchor = {"name": name, "number": number}
                anchors.append(anchor)
            return anchors
    
        # 精炼我们的函数
        def __refine(self, anchors):
    
            express = lambda anchor: {
                'name': anchor['name'][0].strip(),
                'number': anchor['number'][0]
            }
            return map(express, anchors)
    
        # 根据number字段值进行排序
        def __sort_anchors(self, anchors):
            anchors = sorted(anchors, key=self.__sort_seed, reverse=True)
            return anchors
    
        def __sort_seed(self, anchor):
            r = re.findall("\d*", anchor['number'])
            number = float(r[0])
            if '万'in anchor['number']:
                number *= 10000
    
            return number
    
        def __show(self, anchors):
            for anchor in anchors:
                print(anchor['name']+'-----'+anchor['number'])
    
        def run(self):
            html = self.__fetch_content()
            anchors = self.__analysis(html)
            anchors = list(self.__refine(anchors))
            anchors = self.__sort_anchors(anchors)
            self.__show(anchors)
    
    
    spider = Spider()
    spider.run()
    

    测试结果


    测试结果.png

    最后显示小小的优化:

     def __show(self, anchors):
    
            # for anchor in anchors:
              # print(anchor['name']+'-----'+anchor['number'])
    
            for rank in range(0, len(anchors)):
                print('rank'+str(rank + 1) + "----" +
                      anchors[rank]['name'] + "----" +
                      anchors[rank]['number'])
    
    

    测试结果:


    测试结果.png

    撒花。。。。花

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