Output Groupby To Csv File Pandas

I have a sample dataset: import pandas as pd df = {'ID': ['H1','H2','H3','H4','H5','H6'], 'AA1': ['C','B','B','X','G','G'], 'AA2': ['W','K','K','A','B','B'], 'na

Solution 1:

The problem is that you are trying to apply a function to_csv which doesn't exist. Anyway, groupby also doesn't have a to_csv method. pd.Series and pd.DataFrame do.

What you should really use is drop_duplicates here and then export the resulting dataframe to csv:

df.drop_duplicates(['AA1','AA2']).to_csv('merged.txt')

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PS: If you really wanted a groupby solution, there's this one that happens to be 12 times slower than drop_duplicates...:

df.groupby(['AA1','AA2']).agg(lambda x:x.value_counts().index[0]).to_csv('merged.txt')

Solution 2:

you can use groupby with head

df.groupby(['AA1', 'AA2']).head(1)