python - 将数据帧的行与同一组合并并将值分配给新列

Question

我想将数据帧的行与同一组合并并将值分配给新列

之前

     x          y         group
0   0.333333    1.000000    0
1   0.750000    0.137931    0
2   1.000000    0.270115    0
3   0.272727    1.000000    1
4   0.727273    0.124294    1
5   1.000000    0.355932    1
6   0.272727    1.000000    2
7   0.727273    0.096591    2
8   1.000000    0.363636    2
9   0.272727    1.000000    3
10  0.727273    0.105556    3
11  1.000000    0.416667    3
12  0.272727    1.000000    4
13  0.727273    0.181818    4
14  1.000000    0.443182    4

之后

     x1          y1         x2          y2              x3          y3
    0.333333    1.000000    0.750000    0.137931    1.000000    0.270115    
    0.272727    1.000000    0.727273    0.124294    1.000000    0.355932    
    0.272727    1.000000    0.727273    0.096591    1.000000    0.363636    
    0.272727    1.000000    0.727273    0.105556    1.000000    0.416667    
    0.272727    1.000000    0.727273    0.181818    1.000000    0.443182    

Answer 1

这是使用pivot_table的一种方法:

# rank of the row within each group
cats = df.groupby('group').group.rank('first').astype(int)

# use pivot_table to transform data
new_df = pd.pivot_table(df, index='group', columns=cats)

# rename to get desired columns
new_df.columns = [f'{x}{y}' for x,y in new_df.columns]

输出:

             x1        x2   x3   y1        y2        y3
group                                                  
0      0.333333  0.750000  1.0  1.0  0.137931  0.270115
1      0.272727  0.727273  1.0  1.0  0.124294  0.355932
2      0.272727  0.727273  1.0  1.0  0.096591  0.363636
3      0.272727  0.727273  1.0  1.0  0.105556  0.416667
4      0.272727  0.727273  1.0  1.0  0.181818  0.443182