python 爬虫豆瓣热门电影学习

本文为学习鱼c论坛相关课程视频笔记，观看原视频访问这里。

Requests，与BeautifulSoup模块的安装

pip install requests
pip install bs4

解析网页内容使用BeautifulSoup模块，将复杂的网页结构转化为书籍目录的形式。

代码示例

import requests
import bs4
res = requests.get("http://movie.douban.com/top250")
soup = bs4.BeautifulSoup(res.text, "html.parser")
targets = soup.find_all("div", class_="hd")   # 这里网页中class与python class重名，用class_代替
for each in targets:
    print(each.a.span.text)  #不加text则带着html代码一起打印

检查网页HTML代码，如下图：

电影标题位于<div class="hd">...</div>标签中，从属关系如下：

div —> a —> span

所以先调用find_all()，找到所有class="hd"的div标签，然后即可按照从属关系取出想要的电影名信息。

值得注意的是，这我想爬取的是第一个span内的名字，如果我想所有名字代码如下：

print(each.a.text)

如果我想指向爬取第二个span内的名字，代码如下：

print(each.a.span.find_next_sibling().text)

下面是完成的爬取代码，方便学习：

import requests
import bs4
import re

def open_url(url):
    # 使用代理
    # proxies = {"http": "127.0.0.1:1080", "https": "127.0.0.1:1080"}
    headers = {'user-agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.98 Safari/537.36'}

    # res = requests.get(url, headers=headers, proxies=proxies)
    res = requests.get(url, headers=headers)

    return res

def find_movies(res):
    soup = bs4.BeautifulSoup(res.text, 'html.parser')

    # 电影名
    movies = []
    targets = soup.find_all("div", class_="hd")
    for each in targets:
        movies.append(each.a.span.text)

    # 评分
    ranks = []
    targets = soup.find_all("span", class_="rating_num")
    for each in targets:
        ranks.append(' 评分：%s ' % each.text)

    # 资料
    messages = []
    targets = soup.find_all("div", class_="bd")
    for each in targets:
        try:
            messages.append(each.p.text.split('\n')[1].strip() + each.p.text.split('\n')[2].strip())
        except:
            continue

    result = []
    length = len(movies)
    for i in range(length):
        result.append(movies[i] + ranks[i] + messages[i] + '\n')

    return result

# 找出一共有多少个页面
def find_depth(res):
    soup = bs4.BeautifulSoup(res.text, 'html.parser')
    depth = soup.find('span', class_='next').previous_sibling.previous_sibling.text

    return int(depth)

def main():
    host = "https://movie.douban.com/top250"
    res = open_url(host)
    depth = find_depth(res)

    result = []
    for i in range(depth):
        url = host + '/?start=' + str(25 * i)
        res = open_url(url)
        result.extend(find_movies(res))

    with open("豆瓣TOP250电影.txt", "w", encoding="utf-8") as f:
        for each in result:
            f.write(each)
   
if __name__ == "__main__":
    main()