Pandas Group By, Aggregate, Then Return A Different Column

Question

I have a pandas DataFrame containing baseball fielding statistics. Each row shows how many games a player has appeared at a given position over the course of his career.

Player	Position	Games
Brock Holt	2B	20
Brock Holt	3B	70
Ben Zobrist	OF	100
Ben Zobrist	2B	15

I want to be able to return one row per player containing the position they played the most over the years. In the example above the resulting DataFrame would be:

Player	Position
Brock Holt	3B
Ben Zobrist	OF

I've been attempting to group by Player and aggregate by Games like so

df.groupby('Player').agg({'Games':['max']})

which simply provides the name of the player and the maximum number of games played at a position and

df.groupby('Player')['Position'].agg({'Games':['max']})

which returns the error "nested renamer is not supported."

Answer 1

You can also just use groupby and max directly as below:

df.groupby(['Player']).max()  

Yields:

           Position Games
Player      
Ben Zobrist OF      100
Brock Holt  3B      70