Python Pandas：将行转换为列标题

Question

我有以下数据框：

Year    Country          medal    no of medals
1896    Afghanistan      Gold        5
1896    Afghanistan      Silver      4
1896    Afghanistan      Bronze      3
1896    Algeria          Gold        1
1896    Algeria          Silver      2
1896    Algeria          Bronze      3

我要这样

Year    Country      Gold   Silver   Bronze
1896    Afghanistan    5      4         3
1896    Algeria        1      2         3

堆叠/堆叠似乎不起作用。

Answer 1

您正在寻找pivot_table：

In [11]: medals = df.pivot_table('no of medals', ['Year', 'Country'], 'medal')

In [12]: medals
Out[12]:
medal             Bronze  Gold  Silver
Year Country
1896 Afghanistan       3     5       4
     Algeria           3     1       2

以及是否要重新排列列：

In [12]: medals.reindex_axis(['Gold', 'Silver', 'Bronze'], axis=1)
Out[12]:
medal             Gold  Silver  Bronze
Year Country
1896 Afghanistan     5       4       3
     Algeria         1       2       3