pandas DataFrame - 如何获得不同玩家的持续时间

Question

I'm new to Python, and am analyzing bidding records using pandas. I'd like to know the duration (time of last bid-time of first bid) of each players (7000 people), but I have no idea how to proceed. See below the data:

name  bids  profit  date    WeekOfYear
JEFF    3   -75    2012-05-25   21
JEFF    13  -325   2012-05-25   21
eQB     1   -25    2012-05-25   21  
eQB     1   -25    2012-07-02   27
eQB     1   -25    2012-07-09   28
alianx  7   -175   2012-05-25   21
alianx  19  -475   2012-05-25   21
alianx  59  -1475  2012-05-26   21
alianx  13  -325   2012-05-26   21
alianx  7   -175   2012-05-27   21


Data columns (total 5 columns):
name_x        95640 non-null object
date          95640 non-null datetime64[ns]

Expected results:

name  duration first_time   last_time
JEFF     1     2012-05-25   2012-05-25
eQB      46    2012-05-25   2012-07-09
alianx   3     2012-05-25   2012-05-27

I'm having trouble calculating the first_time and last_time of each player, once tried:

data['last_time'] = data.groupby(['date','name_x']).max().reset_index()

But it seems not working. Thanks in advance!

Answer 1

I am not sure about your data based on what you proposed above (ie I didn't see name_x in the dataframe, but assume it must be there). I would try:

data['last_time'] = data.groupby(['name_x'])['date'].transform('max')