列表理解返回最高值

Question

我要报废一个网页，我需要知道有多少页要报废。具体如下：

<div class="pagination">
    <a href="/travel__world-desktop-wallpapers/page/2">2</a>
    <a href="/travel__world-desktop-wallpapers/page/3">3</a>
    <a href="/travel__world-desktop-wallpapers/page/4">4</a>
    ...
    <a href="/travel__world-desktop-wallpapers/page/31">31</a>
    <a href="/travel__world-desktop-wallpapers/page/32">32</a>
    <a href="/travel__world-desktop-wallpapers/page/33">33</a>
    <a href="/travel__world-desktop-wallpapers/page/2">Next »</a>
</div>

如何设置一个返回最多页数（在本例中为33页）的列表理解？你知道吗

Answer 1

不需要。而是设置生成器表达式：

max(int(link.text) 
    for link in soup.find('div', class_='pagination').find_all('a')
    if link.text.strip().isdigit())

演示：

>>> from bs4 import BeautifulSoup
>>> soup = BeautifulSoup('''\
... <div class="pagination">
...     <a href="/travel__world-desktop-wallpapers/page/2">2</a>
...     <a href="/travel__world-desktop-wallpapers/page/3">3</a>
...     <a href="/travel__world-desktop-wallpapers/page/4">4</a>
...     ...
...     <a href="/travel__world-desktop-wallpapers/page/31">31</a>
...     <a href="/travel__world-desktop-wallpapers/page/32">32</a>
...     <a href="/travel__world-desktop-wallpapers/page/33">33</a>
...     <a href="/travel__world-desktop-wallpapers/page/2">Next »</a>
... </div>
... ''')
>>> max(int(link.text) for link in soup.find('div', class_='pagination').find_all('a') if link.text.strip().isdigit())
33