![](/img/trans.png)
[英]Pandas Set multiple column and row values to nan based on another dataframe
[英]How set values in pandas dataframe based on NaN values of another column?
我有名为df
数据(4361, 15)
其原始形状为(4361, 15)
。 agefm
列的某些值为NaN。 只是看看:
> df[df.agefm.isnull() == True].agefm.shape
(2282,)
然后创建新列并将其所有值设置为0:
df['nevermarr'] = 0
所以我想将nevermarr
值设置为1,然后在那一行agefm
是Nan:
df[df.agefm.isnull() == True].nevermarr = 1
没有改变:
> df['nevermarr'].sum()
0
我究竟做错了什么?
最好是使用numpy.where
:
df['nevermarr'] = np.where(df.agefm.isnull(), 1, 0)
print (df)
agefm nevermarr
0 NaN 1
1 5.0 0
2 6.0 0
或使用loc
, ==True
可以省略:
df.loc[df.agefm.isnull(), 'nevermarr'] = 1
或mask
:
df['nevermarr'] = df.nevermarr.mask(df.agefm.isnull(), 1)
print (df)
agefm nevermarr
0 NaN 1
1 5.0 2
2 6.0 3
样品:
import pandas as pd
import numpy as np
df = pd.DataFrame({'nevermarr':[7,2,3],
'agefm':[np.nan,5,6]})
print (df)
agefm nevermarr
0 NaN 7
1 5.0 2
2 6.0 3
df.loc[df.agefm.isnull(), 'nevermarr'] = 1
print (df)
agefm nevermarr
0 NaN 1
1 5.0 2
2 6.0 3
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.