pandas Pivot_Table保留顺序 [英] Pandas pivot_table preserve order

问题描述

>>> df
   A   B   C      D
0  foo one small  1
1  foo one large  2
2  foo one large  2
3  foo two small  3
4  foo two small  3
5  bar one large  4
6  bar one small  5
7  bar two small  6
8  bar two large  7
>>> table = pivot_table(df, values='D', index=['A', 'B'],
...                     columns=['C'], aggfunc=np.sum)
>>> table
          small  large
foo  one  1      4
     two  6      NaN
bar  one  5      4
     two  6      7

我希望输出如上所示，但是得到排序的输出. bar位于foo之上，依此类推.

I want the output to be as shown above, but I get a sorted output. bar comes above foo and so on.

推荐答案

在创建pivot_table时，索引是按字母顺序自动排序的.不仅foo和bar，您还可能会注意到small和large已排序.如果要在顶部放置foo，则可能需要使用sortlevel再次sort.如果您希望像此处的示例中那样进行输出，然后可能都需要同时对A和C进行排序.

While creating pivot_table, the index is automatically sorted alphabetically. Not only foo and bar, you may also notice small and large is sorted. If you want foo on top, you may need to sort them again using sortlevel. If you are expecting output as in example here, then sorting on A and C both may be needed.

table.sortlevel(["A","B"], ascending= [False,True], sort_remaining=False, inplace=True)
table.sortlevel(["C"], axis=1, ascending=False,  sort_remaining=False, inplace=True)
print(table)

输出:

C        small  large
A   B                
foo one  1.0    4.0  
    two  6.0    NaN   
bar one  5.0    4.0  
    two  6.0    7.0  

更新:

要删除索引名称A，B和C:

table.columns.name = None
table.index.names = (None, None)

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