string - Python Pandas : How to replace string contain "?"

Question

我有一个 Python 2.7 Pandas 数据框架，如下所示:

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

我想将字符串“?v=”的一部分替换为其他字符串，例如“URL”列中的“ppp”。我尝试使用普通替换命令:

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

但出现以下错误。

error: nothing to repeat.

当我尝试仅替换一个字符时，例如:

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

效果很好。为什么当我尝试替换字符串“？v =”时它不起作用？

Answer 1

您需要通过\转义？:

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=...

另一个解决方案 Series.replace :

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=...