无法成功运行列表理解 python 中的列表列表

Question

我正在尝试向列表中的链接添加一个 'https:' 前缀，如果它们没有开头的话。但是，当我运行这样做时，现有列表没有任何反应。谁能告诉我为什么？

pdf = ['//www.website.com/pdf_file.pdf', '//www.website2.com/pdf_file.pdf']
con = []
redir = ['//www.redirectlink.com/download']
no_anchor_pdf = []

lol = [pdf, con, redir, no_anchor_pdf]


for l in lol:
    try:
        if l[0][0:6] != 'https:' and l[0][0:6] != 'http:/':
            l =  ['https:' + item for item in l]
            print('added prefix')
        else:
            pass
    except:
        pass

Answer 1

尝试使用正则表达式来简化解决方案

pdf = ['//www.website.com/pdf_file.pdf', '//www.website2.com/pdf_file.pdf']
con = ['https://whosebug.com/']
redir = ['//www.redirectlink.com/download']
no_anchor_pdf = []

lol = [*pdf, *con, *redir, *no_anchor_pdf]

import re
for i in range(len(lol)):
    if re.match('^https',lol[i]):
        continue
    else:
        res=f'https:{lol[i]}'
        lol[i]=res
print(lol)
#['https://www.website.com/pdf_file.pdf', 'https://www.website2.com/pdf_file.pdf', 'https://whosebug.com/', 'https://www.redirectlink.com/download']

无法成功运行列表理解 python 中的列表列表

Can't successfully run list comprehension on list of lists in python

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无法成功 运行 列表理解 python 中的列表列表

Can't successfully run list comprehension on list of lists in python

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无法成功运行列表理解 python 中的列表列表