如何有条件地替换 pandas 数据框列中的子字符串? [英] How to replace a sub-string conditionally in a pandas dataframe column?

问题描述

我有一系列字符串(时间戳)，我想有条件地替换这些字符串中的子字符串:- 如果有+"字符，我想用-"替换它- 或者相反，如果有'-'字符，我想用'+'替换它

I have a Series of strings (timestamps) and I would like to conditionally replace sub-string inside these strings: - if there is a '+' character, I want to replace it with '-' - or on the opposite, if there is a '-' character, I want to replace it with a '+'

我显然不能在没有条件的情况下简单地使用replace()，或者最后，所有+ &- 将转换为单个 + 字符.

I obviously cannot use simply replace() without condition, or in the end, all + & - will be converted to a single + character.

mySeries = mySeries.str.replace('+','-', regex=False)
mySeries = mySeries.str.replace('-','+', regex=False)

请问，我该如何操作这个符号反转?

Please, how should I operate this sign inversion?

我提前感谢您的帮助.祝你有美好的一天，

I thank you in advance for your help. Have a good day,

最佳，

皮埃尔

推荐答案

您可以将正则表达式与接收匹配对象的 lambda 函数一起使用:

You can use regex with lambda function that receives the match object:

0    qqq--++www++
1      1234+5678-
dtype: object

s.str.replace(pat=r"\+|-", repl= lambda mo: "+" if mo.group()=="-" else "-", regex=True)

0    qqq++--www--
1      1234-5678+
dtype: object

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