Pandas Dataframe: Finding entries that share values (e.g. all games that contain a player)

Question

I have a CSV file of game history for my badminton club. I would like to be able to find out information about games that contain a given player (eg who did "Bill" play most with?). Here's an example of what two rounds of three games might look like:

import pandas as pd
player_data = player_data = pd.DataFrame(data=[
('2018-06-12', 1, 1, 1, 'Adam'),
 ('2018-06-12', 1, 1, 2, 'Bill'),
 ('2018-06-12', 1, 1, 3, 'Cindy'),
 ('2018-06-12', 1, 1, 4, 'Derek'),
 ('2018-06-12', 1, 2, 1, 'Edward'),
 ('2018-06-12', 1, 2, 2, 'Fred'),
 ('2018-06-12', 1, 2, 3, 'George'),
 ('2018-06-12', 1, 2, 4, 'Harry'),
 ('2018-06-12', 1, 3, 1, 'Ian'),
 ('2018-06-12', 1, 3, 2, 'Jack'),
 ('2018-06-12', 1, 3, 3, 'Karl'),
 ('2018-06-12', 1, 3, 4, 'Laura'),
 ('2018-06-12', 2, 1, 1, 'Karl'),
 ('2018-06-12', 2, 1, 2, 'Cindy'),
 ('2018-06-12', 2, 1, 3, 'Bill'),
 ('2018-06-12', 2, 1, 4, 'Derek'),
 ('2018-06-12', 2, 2, 1, 'Max'),
 ('2018-06-12', 2, 2, 2, 'George'),
('2018-06-12', 2, 2, 3, 'Fred'),
 ('2018-06-12', 2, 2, 4, 'Ian'),
 ('2018-06-12', 2, 3, 1, 'Nigel'),
 ('2018-06-12', 3, 3, 2, 'Edward'),
 ('2018-06-12', 3, 3, 3, 'Harry'),
 ('2018-06-12', 3, 3, 4, 'Adam')],   
columns=['Date', 'Round #', 'Court #', 'Space', 'Name'])

However, as each row is an individual player's entry, simply locating by name, eg

player_data.loc[player_data['Name'] == 'Bill']

is just going to return only Bill's individual entries, like so:

    Date    Round # Court # Space   Name

    1 2018-06-12    1   1   2   Bill
    14 2018-06-12   2   1   3   Bill

... when what I want is a new dataframe that contains ALL entries of games that Bill has played in, such that in this case it would display as:

Date    Round # Court # Space   Name
0   2018-06-12  1   1   1   Adam
1   2018-06-12  1   1   2   Bill
2   2018-06-12  1   1   3   Cindy
3   2018-06-12  1   1   4   Derek
12  2018-06-12  2   1   1   Karl
13  2018-06-12  2   1   2   Cindy
14  2018-06-12  2   1   3   Bill
15  2018-06-12  2   1   4   Derek

I'm thinking it might be easier to convert the original dataframe to one where each entry is a separate game with all the player names for that game listed in a tuple, so then it'd be relatively simple to check "if name in Names"? eg

Date    Round # Court # Names
    0   2018-06-12  1   1   (Adam, Bill, Cindy, Derek)

... but maybe that'd cause other problems.

Answer 1

After the filter using merge

s1=player_data.loc[player_data['Name'] == 'Bill',['Date','Round #','Court #']]
s2=s1.merge(player_data,how='left')
s2
Out[12]: 
         Date  Round #  Court #  Space   Name
0  2018-06-12        1        1      1   Adam
1  2018-06-12        1        1      2   Bill
2  2018-06-12        1        1      3  Cindy
3  2018-06-12        1        1      4  Derek
4  2018-06-12        2        1      1   Karl
5  2018-06-12        2        1      2  Cindy
6  2018-06-12        2        1      3   Bill
7  2018-06-12        2        1      4  Derek

Answer 2

My method for this is :

bill_player_data = player_data.loc[player_data['Name'] == 'Bill']
ro = bill_player_data['Round #']
co = bill_player_data['Court #']
bill = player_data.loc[player_data['Round #'].isin(ro)]
bill = bill.loc[bill['Court #'].isin(co)]
bill