提取列表中字符串的最后 n 個字符

Question

我有一個鏈接列表，其中有些有頁碼，有些沒有。 我正在嘗試抓取網站以獲取頁碼，但它采用以下格式：'\n\n\n\n\n\n\n\n«\nPrevious\n\n\n\n\n \n\n1\n\n2\n\n3\n\n\x85\n\n23'

有人可以幫我提取列表的最后 2 個字符嗎？

這是我正在使用的代碼和我得到的 output。

for i in range(0, len(links)):
    url = links[i]
    response = requests.get(url, cookies)
    soup = BeautifulSoup(response.content)
    pr = [f.text for f in soup.find_all(class_='lia-paging-full-wrapper lia-paging-pager lia-paging-full-left-position lia-discussion-page-message-pager lia-forum-topic-page-gte-5-pager lia-component-message-pager')]
    ed = [i.split('\n\n\n\n\n\nNext\n»\n\n\n\n', 1)[0] for i in pr]
    print(ed)

我得到的 output 是這樣的：

['\n\n\n\n\n\n\n\n«\nPrevious\n\n\n\n\n\n\n1\n\n2\n\n3\n\n\x85\n\n23']
[]
['\n\n\n\n\n\n\n\n«\nPrevious\n\n\n\n\n\n\n1\n\n2\n\n3']
['\n\n\n\n\n\n\n\n«\nPrevious\n\n\n\n\n\n\n1\n\n2\n\n3']
[]
[]
[]
[]
['\n\n\n\n\n\n\n\n«\nPrevious\n\n\n\n\n\n\n1\n\n2']
['\n\n\n\n\n\n\n\n«\nPrevious\n\n\n\n\n\n\n1\n\n2\n\n3\n\n\x85\n\n16']
[]
[]
[]
['\n\n\n\n\n\n\n\n«\nPrevious\n\n\n\n\n\n\n1\n\n2']
[]

我怎樣才能得到最后 2-3 個字符，因為它們代表頁碼？

Answer 1

你可以做ed[-2:]但我注意到你有 1 到 2 位數字，有很多方法，一種方法是使用正則表達式查找字符串最后的數字：

import re
pattern = re.compile('\d+$')
for i in range(0, len(links)):
    url = links[i]
    response = requests.get(url, cookies)
    soup = BeautifulSoup(response.content)
    pr = [f.text for f in soup.find_all(class_='lia-paging-full-wrapper lia-paging-pager lia-paging-full-left-position lia-discussion-page-message-pager lia-forum-topic-page-gte-5-pager lia-component-message-pager')]
    ed = [i.split('\n\n\n\n\n\nNext\n»\n\n\n\n', 1)[0] for i in pr]
    print(ed)
    if ed:
        page_count = pattern.findall(ed[0])
        print(page_count[0])
    else:
        print('ed is empty!')

OUTPUT：

23
ed is empty!
3
3
ed is empty!
ed is empty!
ed is empty!
ed is empty!
2
16
ed is empty!
ed is empty!
ed is empty!
2
ed is empty!