Python Pandas:如何替换包含“?"的字符串 [英] Python Pandas: How to replace string contain "?"

问题描述

我有一个 Python 2.7 Pandas 数据框，如下所示:

I have a Python 2.7 Pandas Data frame like following:

Id      Title             URL
Id-1    Bruce Almighty    https://www.youtube.com/watch?v=5VGyTOGxyVA
Id-2    Superhero Movie   https://www.youtube.com/watch?v=3BnXz-7-y-o
Id-3    Taken             https://www.youtube.com/watch?v=vjbfiOERDYs
Id-4    Forest Gump       https://www.youtube.com/watch?v=eJFkCJySHdY&t=524s

我想用其他一些字符串替换字符串?v="的一部分，例如URL"列中的ppp".我用普通的替换命令试过:

I want to replace part of string "?v=" with some other string, for example "ppp"from the column "URL". I tried by normal replace command:

df['URL'] = df['URL'].str.replace('?v=', 'ppp')

但出现以下错误.

error: nothing to repeat.

当我尝试只替换一个字符时，例如:

When I try by replacing only one character, for example:

df['URL'] = df['URL'].str.replace('?', 'ppp')

它工作正常.为什么当我尝试替换字符串?v="时它不起作用?

it works fine. Why it didn't work when I try to replace string "?v=" ?

推荐答案

You need escape ? by \:

You need escape ? by \:

df['URL'] = df['URL'].str.replace('\?v=', 'ppp')
print (df)
     Id            Title                                                URL
0  Id-1   Bruce Almighty        https://www.youtube.com/watchppp5VGyTOGxyVA
1  Id-2  Superhero Movie        https://www.youtube.com/watchppp3BnXz-7-y-o
2  Id-3            Taken        https://www.youtube.com/watchpppvjbfiOERDYs
3  Id-4      Forest Gump  https://www.youtube.com/watchpppeJFkCJySHdY&t=...

Series.replace 的另一种解决方案:

df['URL'] = df['URL'].replace('\?v=', 'ppp', regex=True)
print (df)
     Id            Title                                                URL
0  Id-1   Bruce Almighty        https://www.youtube.com/watchppp5VGyTOGxyVA
1  Id-2  Superhero Movie        https://www.youtube.com/watchppp3BnXz-7-y-o
2  Id-3            Taken        https://www.youtube.com/watchpppvjbfiOERDYs
3  Id-4      Forest Gump  https://www.youtube.com/watchpppeJFkCJySHdY&t=...

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