爬虫案例：使用re,requests,json,RequestException爬取猫眼电影Top100加保存文件

#python3.7
#author:huangtao
#pycharm

import requests
from requests.exceptions import RequestException
import re
import json
#导入相关库文件
#定义get_url,通过主程序传递的url进行访问
def get_url(url,headers):
#判断访问是否成功,如果响应值为200,则访问成功
    try:
        response = requests.get(url,headers=headers)
        #访问url
        if response.status_code == 200:
            return response.text
            #返回网页源代码
        else:
            return None
    except RequestException:
        return None
    #否则返回None


def parse_html(html):
#定义def parse_html,通过解析从上面得到的html源代码,解析数据
    ranks = re.findall(r'(.*?)',html,re.DOTALL)
    titles = re.findall(r'
(.*?)
',html,re.DOTALL)
    lianjies = re.findall(r'',html,re.DOTALL)
    authors_list = re.findall(r'
(.*?)
', html, re.DOTALL)
    releasetimes = re.findall(r'
(.*?)
',html,re.DOTALL)
    scores = re.findall(r'(.*?)(.*?)',html,re.DOTALL)
    #通过正则解析网页得到数据
    for rank,title,lianjie,authors,releasetime,score in zip(ranks,titles,lianjies, authors_list,releasetimes,scores):
        # print(authors.strip())
        movie = []
        #定义一个movie
        movies = {
                '排名':rank,
                '电影名':title,
                '海报链接':lianjie,
                '主演':authors.strip()[3:],
                '上映时间/国家':releasetime[5:],
                '分数':score[0]+score[1]
            }

        movie.append(movies)
        print(movie)


        with open('movie','a',encoding='utf-8')as f:
            f.write(json.dumps(movie,ensure_ascii=False)+'\n')
            f.close()
        #保存数据到movie.txt中,movie先转下格式,然后保存,保存的时候要转码


def main(offset):
    url = 'http://maoyan.com/board/4?offset='+str(offset)
    headers = {'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) '
               'AppleWebKit/537.36 (KHTML, like Gecko) '                 
               'Chrome/70.0.3538.77 Safari/537.36'}
    html = get_url(url,headers)
    parse_html(html)
#main方法,传递各种参数,构造url



if __name__ == '__main__':
#主程序
    for i in range(10):
#循环遍历
        main(i*10)