pandas pivot_table 保持索引

Question

我有一个数据框：

import pandas as pd

data = {'day_bucket': ['2011-01-21', '2011-01-22', '2011-01-23', '2011-01-24'], 'label': ['birds', 'birds', 'birds', 'birds'], 'numeric_value': [4, 0, 7, 3]}

df = pd.DataFrame(data)

   day_bucket  label  numeric_value
0  2011-01-21  birds              4
1  2011-01-22  birds              0
2  2011-01-23  birds              7
3  2011-01-24  birds              3

我想旋转这个数据框，以便我有一个列birds ，其下面的值。

pd.pivot_table(df, values='numeric_value', index='day_bucket',columns='label')  

给出：

label       birds
day_bucket             
2011-01-21  4
2011-01-22  0
2011-01-23  7
2011-01-24  3

我该怎么做才能保持索引？ 结果将如下所示：

    day_bucket birds    
0   2011-01-21  4
1   2011-01-22  0
2   2011-01-23  7
3   2011-01-24  3 

Answer 1

set_index与append

df.set_index(['day_bucket', 'label'], append=True) \
  .rename_axis([None, None, None]).squeeze().unstack()


              birds
0 2011-01-21      4
1 2011-01-22      0
2 2011-01-23      7
3 2011-01-24      3

Answer 2

与此同时，我也想出了一个结果

pd.pivot_table(df, values='numeric_value', 
                   index=[df.index.values,'day_bucket'],
                   ,columns='label').reset_index('day_bucket')

label  day_bucket  mortality_birds
0      2011-01-21                4
1      2011-01-22                0
2      2011-01-23                7
3      2011-01-24                3

Answer 3

仅供补充：

pt2 = pt.rename_axis(None, axis=1).reset_index()
print(pt2)

   day_bucket  birds
0  2011-01-21      4
1  2011-01-22      0
2  2011-01-23      7
3  2011-01-24      3

---

用于它的数据框是：

df = pd.DataFrame({'day_bucket': ['2011-01-21', '2011-01-22', '2011-01-23', '2011-01-24'],
                   'label': ['birds', 'birds', 'birds', 'birds'],
                   'num_value': [4, 0, 7, 3]})

pt = pd.pivot_table(df,
                    values='num_value',
                    index='day_bucket',
                    columns='label',
                    aggfunc=np.sum)
print(pt, '\n')

label       birds
day_bucket       
2011-01-21      4
2011-01-22      0
2011-01-23      7
2011-01-24      3