With Pandas in Python, select the highest value row for each group

Question

With Pandas, for the following data set

author1,category1,10.00
author1,category2,15.00
author1,category3,12.00
author2,category1,5.00
author2,category2,6.00
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Answer 1

import pandas as pd

df = pd.read_csv("in.csv", names=("Author","Cat","Val"))

print(df.groupby(['Author'])['Val'].max())

To get the df:

inds = df.groupby(['Author'])['Val'].transform(max) == df['Val']
df = df[inds]
df.reset_index(drop=True, inplace=True)
print(df)
    Author        Cat  Val
0  author1  category2   15
1  author2  category4    9
2  author3  category1    7
3  author3  category3    7