案例21：爬虫取书名、评分、价格

import requests
#引入requests库
from bs4 import BeautifulSoup
#引入bs库
res = requests.get('http://books.toscrape.com/')
#请求数据
soup = BeautifulSoup(res.text,'html.parser')
#解析数据
aaa = soup.find('ul',class_="nav nav-list").find('ul').find_all('li')
#查找数据：li标签、ul标签多，无法直接查找，需要多层嵌套精准定位
iii = []#大列表用于储存
for i in aaa:
    bbb = i.text.strip()
    iii.append(bbb)
print(iii)

import requests
from bs4 import BeautifulSoup

res = requests.get('http://books.toscrape.com/catalogue/category/books/travel_2/index.html')
soup = BeautifulSoup(res.text, 'html.parser')
article = soup.find_all('article', class_='product_pod')

for item in article:
    name_h3 = item.find('h3')  # 找到书名所在标签h3中
    name_a = name_h3.find('a')
    name = name_a['title']  # 找到每本书的全名
    print(name)
    score_p = item.find('p')
    score_dirt = score_p.attrs  # 这一步是取出p标签的属性名（以大字典的形式）
    # print(score_dirt)
    score = score_dirt['class'][1]
    print(score)  # 取出分
    price = item.find('p', class_='price_color')  # 取出价格
    print(price.text[1:]+'\n')  # 注意偏移量