练习9：BeautifulSoup和CSS选择器 📕

💡 知识点回顾

课程位置：07.处理数据的方法.pdf - 7.3 BeautifulSoup

核心方法：

• soup.find(tag, attrs) - 查找第一个匹配的标签
• soup.find_all(tag, attrs) - 查找所有匹配的标签
• soup.select(selector) - 使用CSS选择器

CSS选择器：

• .class - 类选择器
• #id - ID选择器
• tag - 标签选择器
• tag.class - 组合选择器
• parent > child - 直接子元素
• parent child - 所有后代元素

💡 示例代码

方法1：使用find和find_all

import requests
from bs4 import BeautifulSoup

url = 'https://req.haleibc.com/practice9'
response = requests.get(url)
soup = BeautifulSoup(response.content, 'lxml')

# 查找所有电影卡片
movies = soup.find_all('div', class_='movie-card')
for movie in movies:
    title = movie.find('h3', class_='movie-title').text
    director = movie.find('p', class_='director').text
    rating = movie.find('span', class_='movie-rating').text
    print(f"{title} - {director} - {rating}")

方法2：使用CSS选择器

import requests
from bs4 import BeautifulSoup

url = 'https://req.haleibc.com/practice9'
response = requests.get(url)
soup = BeautifulSoup(response.content, 'lxml')

# 使用CSS选择器
titles = soup.select('h3.movie-title')
for title in titles:
    print(title.text)

# 组合选择器
directors = soup.select('.movie-card .director')
for director in directors:
    print(director.text)

# 提取属性
movie_ids = soup.select('.movie-card')
for movie in movie_ids:
    print(f"ID: {movie['data-id']}")

方法3：完整提取

import requests
from bs4 import BeautifulSoup

url = 'https://req.haleibc.com/practice9'
response = requests.get(url)
soup = BeautifulSoup(response.content, 'lxml')

# 提取所有电影信息
movies = []
for card in soup.select('.movie-card'):
    movie = {
        'id': card['data-id'],
        'title': card.select_one('.movie-title').text,
        'director': card.select_one('.director').text,
        'year': card.select_one('.year').text,
        'genre': card.select_one('.genre').text,
        'rating': card.select_one('.movie-rating').text
    }
    movies.append(movie)
    print(movie)