CODEWITHSUNDEEP
pythonpandas
dr_rk
dr_rk

Reputation: 4565

Set values of a dataframe based on a second dataframe

I would like to mask a Pandas dataframe based on booleans in another dataframe.

So, I've created a pandas DataFrame of 1 and 0:

boolean_data = [(1, 0), (0, 1), (0, 0)]
df_criteria = DataFrame(data=boolean_data, index=['A','B','C'], columns=['x','y'])

    x    y
A   1    0
B   0    1
C   0    0

I would like to use the above df_criteria to mask values of a second dataframe df_result, i.e., where df_criteria(i,j)=1, df_result(i,j)=0. 

df_result = DataFrame(
    data=[(10, 20), (30, 20), (10, 10)],
    index=['A','B','C'], columns=['x','y'])

df_result (before masking)

   x    y
A  10   20
B  30   20
C  10   10

df_result (after masking)

   x    y
A  0   20
B  30   0
C  10  10

Upvotes: 2

Views: 74

Answers (2)

jpp
jpp

Reputation: 164673

Using pd.DataFrame.iloc and numpy.where:

df.iloc[:] = np.where(df_criteria, 0, df)

print(df)

    x   y
A   0  20
B  30   0
C  10  10

Upvotes: 1

BENY
BENY

Reputation: 323266

IIUC, Using mask

df_result.mask(df_criteria==1,0)
Out[55]: 
    x   y
A   0  20
B  30   0
C  10  10

Upvotes: 3

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