How can you remove only the interaction terms in a polynomial regression using scikit-learn?

Question

I am running a polynomial regression using scikit-learn. I have a large number of variables (23 to be precise) which I am trying to regress using polynomial regression with degree 2.

interaction_only = True, keeps only the interaction terms such as X₁*Y₁, X₂*Y₂, and so on.

I want only the other terms i.e, X₁, X₁², Y₁, Y₁², and so on.

Is there a function to get this?

Answer 1

There is no such function, because the transormation can be easily expressed with numpy itself.

X = ... 
new_X = np.hstack((X, X**2))

and analogously if you want to add everything up to degree k

new_X = np.hstack((X**(i+1) for i in range(k)))