That is intended to test for the first ii
In Python, the first ii value is 0
Z(1:4) = linspace(t1,t2,4)
In MATLAB, that would be the first four entries in Z
Z[1,3] = np.linspace(t1,t2,3)
You have asked python to create a list with three elements (not 4 like you did in MATLAB), and you have asked Python to assign it to single location in a 2D array. If you were wanting to assign to the first three elements in Z then you should assigning to Z[0:2] .
It is not clear to me why you changed from 4 elements in MATLAB into 3 elements in Python.