Perform an operation on all pairs of rows in a column

Question

Assume the following DataFrame:

id    A   
1     0
2     10
3     200
4     3000

I would like to make a calculation betweeen all rows to all ot

Answer 1

IIUC itertools

import itertools

s=list(itertools.combinations(df.index, 2)) 
pd.Series([df.A.loc[x[1]]-df.A.loc[x[0]] for x in s ])
Out[495]: 
0      10
1     200
2    3000
3     190
4    2990
5    2800
dtype: int64

Update

s=list(itertools.combinations(df.index, 2)) 

pd.DataFrame([x+(df.A.loc[x[1]]-df.A.loc[x[0]],) for x in s ])
Out[518]: 
   0  1     2
0  0  1    10
1  0  2   200
2  0  3  3000
3  1  2   190
4  1  3  2990
5  2  3  2800