cartesian product in pandas

Question

I have two pandas dataframes:

from pandas import DataFrame
df1 = DataFrame({\'col1\':[1,2],\'col2\':[3,4]})
df2 = DataFrame({\'col3\':[5,6]})     
         


        

Answer 1

You can use numpy as it could be faster. Suppose you have two series as follows,

s1 = pd.Series(np.random.randn(100,))
s2 = pd.Series(np.random.randn(100,))

You just need,

pd.DataFrame(
    s1[:, None] @ s2[None, :], 
    index = s1.index, columns = s2.index
)