Pandas where

In [20]: df
Out[20]:
   A  B  C
0  1  2  1
1  2  3  0
2  3  4  0
3  4  5  1

# Note that df.C is a mask
# Note that this is np.where, not df.where. That is different.
In [21]: df['D'] = np.where(df.C, df.A, df.B)

In [22]: df
Out[22]:
   A  B  C  D
0  1  2  1  1
1  2  3  0  3
2  3  4  0  4
3  4  5  1  4

Source: stackoverflow.com

Similar codes

1 vote102 views2 answers
Number of digits calculation
Python
0 vote102 views1 answer
Cufflink install python jupyter
Python
-1 vote112 views1 answer
Cannot import name 'SGD' from 'keras.optimizers'
Python
0 vote98 views1 answer
IndexError: tuple index out of range
Python
0 vote96 views1 answer
Flask decorator causes views to be named the same thing
Python
0 vote91 views1 answer
How to pause a thread in python
Python
-1 vote115 views6 answers
List comprehension python
Python
0 vote104 views1 answer
Numpy stack arrays vertically
Python
0 vote106 views1 answer
Find percentage of missing values in a column in python
Python
0 vote144 views2 answers
Pandas split column with tuple
Python