python-3.x - 屏蔽与另一组数据不相等的数据并存储结果

Question

有谁知道如何修改“更改”数据框以仅评估真实的单元格？我只想将那些项目发送到 df2 中的更改，从 df1 到更改数据框。这会替换所有单元格，我不能单独使用“掩码”，因为它是多维的。谢谢!

import pandas as pd
import numpy as np 
df1=pd.DataFrame({'Col1' : ['blue', 2, 3, 4], 'Col2' : [90, 99, 3, 97], 'Col3' : [11, 12, 13, 14]})
df2=pd.DataFrame({'Col1' : ['blue', 2, 6], 'Col2' : [90, 99, 99], 'Col3' : [11, 12, 13]})
mask=df2.ne(df1)
#Line in question    
changes=(df1.loc[mask.index].astype(str) + ' changed to: ***' + df2.loc[mask.index].astype(str)).fillna(df2.astype(str))

我希望输出看起来像:

Col1    Col2    Col3
0   blue    90  11
1   2   99  12
2   3 changed to: ***6  3 changed to: ***99.0   13
3   4 changed to: ***nan    97 changed to: ***nan   14 changed to: ***nan

Answer 1

IIUC，您可以将where 与other 参数一起使用see docs :

df1.where(df1.eq(df2), changes)

输出:

                   Col1                   Col2                   Col3
0                  blue                     90                     11
1                     2                     99                     12
2    3 changed to: ***6  3 changed to: ***99.0                     13
3  4 changed to: ***nan  97 changed to: ***nan  14 changed to: ***nan