saving various 2D matrices into a 3D matrix in python

Question

I am trying to save various 2D matrices from python into a 3D matrix, but I'm receiving an error, here are the matrices:

rho=np.zeros((Nx,Nt))
p=np.zeros((Nx,Nt))
u=np.zeros((Nx,Nt))
U=np.zeros((Nx,Nt,3))
F=np.zeros((Nx,Nt,3))

I'm trying to save combinations of the first three into the last two like this:

F[:][:][0]=u*rho
F[:][:][1]=p*u**2+p
F[:][:][2]=u(e + p)

know that e is another NX by Nt matrix in another part of the code, it seems I'm not assigning this properly as I get an error saying I can't save a 1000*1000 matrix into a 1000*3 matrix, which is understandable, but of course my idea is to save the 1000*1000 matrix into the first "element" of my 3d matrix F and other combinations into my U matrix and so on, can anyone tell me how to do this, saving the 2d matrices into indexes of 3d matrices, I also tried with U[0][:][:]=rho

Answer 1

正如Divakar指出的那样，我没有正确使用索引，使用F[:,:,0]=u*rho等，纠正了问题。