A B
abc AN
abd BN
a01 CN
abc BN
a02 CN
I have a dataframe similar to above. For every B=CN,I want to replace corresponding row in A i.e a01,a02 with value from dictionary.
The dictionary is as follow:
d={'a01':'ana','a02':'aza'}
Whenever I'm trying to replace the values, it's giving incorrect result either the values are misplaced. I tried where clause as well but still missing something.
In a single line in would look like this:
df.loc[df['B'].eq('CN'), 'A'] = df['A'].map(d)
df
A B
0 abc AN
1 abd BN
2 ana CN
3 abc BN
4 aza CN
Also you can use np.where:
df['A'] = np.where(df['B'].eq('CN'), df['A'].map(d), df['A'])
Here is the whole code with np.where:
import pandas as pd
import numpy as np
df = pd.DataFrame({'A': ['abc', 'abd', 'a01', 'abc', 'a02'],
'B': ['AN', 'BN', 'CN', 'BN', 'CN']})
d = {'a01': 'ana', 'a02': 'aza'}
df['A'] = np.where(df['B'].eq('CN'), df['A'].map(d), df['A'])
df
A B
0 abc AN
1 abd BN
2 ana CN
3 abc BN
4 aza CN
Use map to use the dictionary for mapping the values and loc to assign the values to the particular slice:
CN = df['B'] == 'CN'
df['A'].loc[CN] = df[CN].A.map(d)
df
A B
0 abc AN
1 abd BN
2 ana CN
3 abc BN
4 aza CN
