Cartesian product from two Series, different lengths and indexes

Question

Given two series:

import pandas as pd
ser1 = pd.Series(data = [1,2,3], index=[1,2,3])
ser2 = pd.Series(data = [1,2,3,4,5],         


        

Answer 1

You can use NumPy broadcasting to multiply the values of one series by the transposed values of the other.

res = pd.DataFrame(ser1.values * ser2.values[:, None],
                   index=ser2.index, columns=ser1.index)

print(res)

   1   2   3
a  1   2   3
b  2   4   6
c  3   6   9
d  4   8  12
e  5  10  15

Answer 2

I think need numpy.outer for outer product of two Series:

df = pd.DataFrame(np.outer(ser2, ser1), index = ser2.index, columns = ser1.index)

print (df)
   1   2   3
a  1   2   3
b  2   4   6
c  3   6   9
d  4   8  12
e  5  10  15