将 nan 值从一个数据框复制到另一个数据框

Question

我有两个数据框 df1 和 df2，它们的大小和尺寸都相同。有没有一种简单的方法可以将 'df1' 中的所有 NaN 值复制到 'df2' ？下面的示例演示了我想要从 .copynans()

得到的输出

In: df1
Out:
                   10053802  10053856  10053898  10058054
2012-07-01 00:00:00     100.0     0.353     0.300     0.326
2012-07-01 00:30:00     101.0     0.522     0.258     0.304
2012-07-01 01:00:00     102.0     0.311     0.369     0.228
2012-07-01 01:30:00     103.0       NaN     0.478     0.247
2012-07-01 02:00:00     101.0       NaN       NaN     0.259
2012-07-01 02:30:00     102.0     0.281       NaN     0.239
2012-07-01 03:00:00     125.0     0.320       NaN     0.217
2012-07-01 03:30:00     136.0     0.288       NaN     0.283

In: df2
Out:  
                    10053802  10053856  10053898  10058054
2012-07-01 00:00:00       1.0        2.0      3.0       4.0
2012-07-01 00:30:00       1.0        2.0      3.0       4.0
2012-07-01 01:00:00       1.0        2.0      3.0       4.0
2012-07-01 01:30:00       1.0        2.0      3.0       4.0
2012-07-01 02:00:00       1.0        2.0      3.0       4.0
2012-07-01 02:30:00       1.0        2.0      3.0       4.0
2012-07-01 03:00:00       1.0        2.0      3.0       4.0
2012-07-01 03:30:00       1.0        2.0      3.0       4.0

In: df2.copynans(df1)
Out:
                     10053802  10053856  10053898  10058054
2012-07-01 00:00:00       1.0       2.0       3.0       4.0
2012-07-01 00:30:00       1.0       2.0       3.0       4.0
2012-07-01 01:00:00       1.0       2.0       3.0       4.0
2012-07-01 01:30:00       1.0       NaN       3.0       4.0
2012-07-01 02:00:00       1.0       NaN       NaN       4.0
2012-07-01 02:30:00       1.0       2.0       NaN       4.0
2012-07-01 03:00:00       1.0       2.0       NaN       4.0
2012-07-01 03:30:00       1.0       2.0       NaN       4.0

Answer 1

#Use null cells from df1 as index to set the the corresponding cell to nan in df2
df2[df1.isnull()]=np.nan

Answer 2

两者都

df1.where(df2.notnull())

或者

df1.mask(df2.isnull())

将 nan 值从一个数据框复制到另一个数据框

Copy nan values from one dataframe to another

python

mask

pandas