用大熊猫为每个组创建一个数据框组合(Create a DataFrame of combinations for each group with pandas)

输入如下。

Out[178]: 
  group value
0     A     a
1     A     b
2     A     c
3     A     d
4     B     c
5     C     d
6     C     e
7     C     a
 
 对于这个输入，我想为每个组创建一个组合并创建一个DataFrame。 我该怎么做？ 
 
 我想要得到的输出： 
 
Out[180]: 
  group  0  1
0     A  a  b
1     A  a  c
2     A  a  d
3     A  b  c
4     A  b  d
5     A  c  d
0     C  d  e
1     C  d  a
2     C  e  a
The inputs are as follows.
 
Out[178]: 
  group value
0     A     a
1     A     b
2     A     c
3     A     d
4     B     c
5     C     d
6     C     e
7     C     a
 
For this input, I want to create a combination for each group and create one DataFrame. How can I do it?
 
The output I want to get:
 
Out[180]: 
  group  0  1
0     A  a  b
1     A  a  c
2     A  a  d
3     A  b  c
4     A  b  d
5     A  c  d
0     C  d  e
1     C  d  a
2     C  e  a

                
最满意答案
                
                    
                        
 使用lambda函数和combinations groupby ： 
 
from  itertools import combinations

df = (df.groupby('group')['value'].apply(lambda x: pd.DataFrame(list(combinations(x,2))))
        .reset_index(level=1, drop=True)
        .reset_index())
print (df)
  group  0  1
0     A  a  b
1     A  a  c
2     A  a  d
3     A  b  c
4     A  b  d
5     A  c  d
6     C  d  e
7     C  d  a
8     C  e  a
Use groupby with lambda function and combinations:
 
from  itertools import combinations

df = (df.groupby('group')['value'].apply(lambda x: pd.DataFrame(list(combinations(x,2))))
        .reset_index(level=1, drop=True)
        .reset_index())
print (df)
  group  0  1
0     A  a  b
1     A  a  c
2     A  a  d
3     A  b  c
4     A  b  d
5     A  c  d
6     C  d  e
7     C  d  a
8     C  e  a