how to combine rows with a key and keep the highest value Pandas-CodePudding

I have one dataframe with several rows and several columns and I need to keep the values from the other columns a,b,c by combining it into a single row of the corresponding key.

Key, ColA, ColB, Colc
111  0     12    0
111  12    0     0
111  0     0     12
222  12    0     0
222  0     0     12

and the output I want is

key, ColA, ColB, ColC
111  12    12    12
222  12    0     12

Thanks for any help

CodePudding user response：

You can use groupby() to get the max value :

import pandas as pd

df = pd.DataFrame({'Key' : [111, 111, 111, 222, 222], 'ColA' : [0, 12, 0, 12, 0], 'ColB' : [12, 0, 0, 0, 0], 'ColC' : [0, 0, 12, 0, 12]})

print(df.groupby(by='Key', as_index = False).max())

# Output :
#    Key  ColA  ColB  ColC
# 0  111    12    12    12
# 1  222    12     0    12

CodePudding user response：

Keep the max of each group:

>>> df.groupby('Key', as_index=False).max()

   Key  ColA  ColB  Colc
0  111    12    12    12
1  222    12     0    12