Setting columns of a matrix

Say I have a matrix(TMatrixD?) and three TArrayD’s(all of equal length). I want three columns of the matrix to be the three arrays. Can I do that without a loop? How?
Thanks in advance.

I figured it out. It’s like this in case anyone ever searches for it:

TMatrixD dataEff(nrows,ncols);
TVectorD deCuts(nrows);