CODEWITHSUNDEEP
pythonpandasdataframe
Mehdi Selbi
Mehdi Selbi

Reputation: 147

getting data from df1 if it doesn't exist in df2

I'm trying to get data from df1 if it doesn't exist in df2 and col1 in df1 should be aligned with col3 in df2 ( same for col2 and col4)

Df1: 

col1  col2   
2     2      
1     Nan    
Nan   1         

Df2:

col3  col4   
Nan   1      
1     Nan    
Nan   1         


Final_Df:

col1  col2   
2     1      
1     Nan    
Nan   1

Upvotes: 2

Views: 141

Answers (2)

Ynjxsjmh
Ynjxsjmh

Reputation: 30052

Just use pandas.DataFrame.update(other). The overwrite parameter explanation.

overwrite bool, default True

How to handle non-NA values for overlapping keys:

  • True: overwrite original DataFrame’s values with values from other.

  • False: only update values that are NA in the original DataFrame.

Note that df.update(other) modifies in place using non-NA values from another DataFrame on matching column label.

df2.update(df1.set_axis(df2.columns, axis=1))

print(df2)

  col3 col4
0    2    2
1    1  Nan
2  Nan    1

Upvotes: 2

Nk03
Nk03

Reputation: 14949

Make the column same / replace Nan with np.NAN / update the dataframe

df1.columns = df2.columns
df2 = df2.replace('Nan', np.NAN)
df2.update(df1, overwrite=False) # will only update the NAN values

Upvotes: 1

Related Questions