Beautifulsoup4错误选择多个属性

Question

我是 bs4 的新手，我正在尝试为大学作业抓取有关亚马逊产品的一些信息，特别是我正在尝试从 html 页面中提取产品类别。我试图以这种方式提取它，但我得到一个空数组。

我需要提取：杂货和美食、糖果和巧克力、果冻豆和软糖、甘草

这是我想抓取的网页部分，但我不知道如何访问：

<div id="wayfinding-breadcrumbs_container" class="a-section a-spacing-none a-padding-medium breadcrumb-fst-exp-1 fst-breadcrumb-feature">
    <ul class="a-unordered-list a-horizontal a-size-small">
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/grocery-breakfast-foods-snacks-organic/b/ref=dp_bc_aui_T1_1?ie=UTF8&node=16310101">
                Grocery & Gourmet Food
            </a>
         </span></li>
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/Candy-Chocolate/b/ref=dp_bc_aui_T1_2?ie=UTF8&node=16322461">
                Candy & Chocolate
            </a>
         </span></li>
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/b/ref=dp_bc_aui_T1_3?ie=UTF8&node=17369013011">
                Jelly Beans & Gummy Candy
            </a>
         </span></li>
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/Licorice-Candy/b/ref=dp_bc_aui_T1_4?ie=UTF8&node=16322521">
                Licorice
            </a>
         </span></li>
    </ul>
</div>

import requests
from bs4 import BeautifulSoup
url = "https://www.amazon.com/dp/" + 'B001GVISJM'
headers = {'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36'}
r = requests.get(url, headers=headers)
soup = BeautifulSoup(r.content, "html.parser")
for divtag in soup.find_all("div", attr={"id" : "wayfinding-breadcrumbs_container"}):
    print(divtag)

Answer 1

你可以像下面这样。对于按 id 查找，您可以将其作为函数参数传递，而不是在 attrs 中传递。

from bs4 import BeautifulSoup

t = '''
<div id="wayfinding-breadcrumbs_container" class="a-section a-spacing-none a-padding-medium breadcrumb-fst-exp-1 fst-breadcrumb-feature">
    <ul class="a-unordered-list a-horizontal a-size-small">
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/grocery-breakfast-foods-snacks-organic/b/ref=dp_bc_aui_T1_1?ie=UTF8&node=16310101">
                Grocery & Gourmet Food
            </a>
         </span></li>
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/Candy-Chocolate/b/ref=dp_bc_aui_T1_2?ie=UTF8&node=16322461">
                Candy & Chocolate
            </a>
         </span></li>
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/b/ref=dp_bc_aui_T1_3?ie=UTF8&node=17369013011">
                Jelly Beans & Gummy Candy
            </a>
         </span></li>
         <li><span class="a-list-item">
            <a class="a-link-normal" href="/Licorice-Candy/b/ref=dp_bc_aui_T1_4?ie=UTF8&node=16322521">
                Licorice
            </a>
         </span></li>
    </ul>
</div>
'''

soup = BeautifulSoup(t, 'html.parser')
for divtag in soup.find_all(id="wayfinding-breadcrumbs_container"):
    for d in divtag.find_all(attrs={'class': 'a-link-normal'}):
        print(d.get_text().strip())

输出：

Grocery & Gourmet Food
Candy & Chocolate
Jelly Beans & Gummy Candy
Licorice

Answer 2

短而快速的选择器（结合面包屑的 id，然后为链接键入选择器 a。

categories = [item['href'] for item in soup.select('#wayfinding-breadcrumbs_feature_div a')]

Answer 3

试试这个：

for i in soup.find('div', id='wayfinding-breadcrumbs_container').find('ul').find_all('li', class_=None):
    text = i.find('a').text.strip()
    print(text)

或

for i in soup.select('#wayfinding-breadcrumbs_container a'):
    text = i.text.strip()
    print(text)

实际的亚马逊页面有另一个您没有考虑的 div。结构是：

<div>
<div> <--- missing in your post
<ul>
<li>
...

附带说明：亚马逊在抓取方面是出了名的挑剔。如果不使用计时器、代理、cookie 和冗余循环，您的爬虫将非常不一致。