pandas - 通过分组创建虚拟变量

Question

我有一个代表玩家、团队和胜利的 DataFrame。我想做的是创建一个新的 DataFrame，其中团队是索引，代表玩家 x 是否在该团队中，以及该团队是否获胜。

pd.DataFrame(data=[['Team A', 1], ['Team B', 0], ['Team B', 0], ['Team A', 1]], columns=['TEAM', 'WIN'], index=['Player 1', 'Player 2', 'Player 3', 'Player 4'])

            TEAM  WIN
Player 1  Team A    1
Player 2  Team B    0
Player 3  Team B    0
Player 4  Team A    1

期望的结果:

pd.DataFrame(data=[[1, 1, 0, 0, 1], [0, 0, 1, 1, 0]], columns=['Player 1', 'Player 2', 'Player 3', 'Player 4', 'WIN'], index=['Team A', 'Team B'])

        Player 1  Player 2  Player 3  Player 4  WIN
Team A         1         1         0         0    1
Team B         0         0         1         1    0

Answer 1

IIUC您可以使用pivot_table()方法:

In [96]: df.reset_index().pivot_table(index='TEAM', columns='index', values='WIN', fill_value=0)
Out[96]:
index   Player 1  Player 2  Player 3  Player 4
TEAM
Team A         1         0         0         1
Team B         0         0         0         0