Python Pandas merge only certain columns

python merge pandas
BubbleGuppies picture BubbleGuppies · Jul 31, 2013 · Viewed 164.8k times · Source

Is it possible to only merge some columns? I have a DataFrame df1 with columns x, y, z, and df2 with columns x, a ,b, c, d, e, f, etc.

I want to merge the two DataFrames on x, but I only want to merge columns df2.a, df2.b - not the entire DataFrame.

The result would be a DataFrame with x, y, z, a, b.

I could merge then delete the unwanted columns, but it seems like there is a better method.

Answer

Arthur D. Howland picture Arthur D. Howland · Mar 13, 2017

You want to use TWO brackets, so if you are doing a VLOOKUP sort of action:

df = pd.merge(df,df2[['Key_Column','Target_Column']],on='Key_Column', how='left')

This will give you everything in the original df + add that one corresponding column in df2 that you want to join.

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