將子水平轉換爲單列

Question

Category      Cat2 average 
Beauty/Wellness/Healthcare 1  54.50 
           2  53.25 
           3  48.00 
           4  57.57 
           5  51.33 
           6  18.50 
           7  16.00 

我有一個數據框，多級。我需要將第二級轉換爲簡單的列。可能嗎？ unstacking創建第1列到第7列。

作爲補充：是否可以重命名組名稱（級別0和1）？

Answer 1

df.reset_index(['Cat2'])會將Cat2索引轉換爲列。

例如，

In [38]: df 
Out[38]: 
            average 
Category      Cat2   
Beauty/Wellness/Healthcare 1  54.50 
           2  53.25 
           3  48.00 
           4  57.57 
           5  51.33 
           6  18.50 
           7  16.00 

In [39]: df.reset_index(['Cat2']) 
Out[39]: 
           Cat2 average 
Category          
Beauty/Wellness/Healthcare  1 54.50 
Beauty/Wellness/Healthcare  2 53.25 
Beauty/Wellness/Healthcare  3 48.00 
Beauty/Wellness/Healthcare  4 57.57 
Beauty/Wellness/Healthcare  5 51.33 
Beauty/Wellness/Healthcare  6 18.50 
Beauty/Wellness/Healthcare  7 16.00 

---

要更改指數級別名稱，使用df.index.names = ['foo', 'bar']：

In [48]: df.index.names = ['foo', 'bar'] 

In [49]: df 
Out[49]: 
            average 
foo       bar   
Beauty/Wellness/Healthcare 1  54.50 
           2  53.25 
           3  48.00 
           4  57.57 
           5  51.33 
           6  18.50 
           7  16.00