Initialize empty matrix in Python

Question

I am trying to convert a MATLAB code in Python. I don\'t know how to initialize empty matrix in Python.

MATLAB Code:

demod4(1) = [];

<

Answer 1

What about initializing a list, populating it, then converting to an array.

demod4 = []  

Or, you could just populate at initialization using a list comprehension

demod4 = [[func(i, j) for j in range(M)] for i in range(N)]

Or, you could initialize an array of all zeros if you know the size of the array ahead of time.

demod4 = [[0 for j in range(M)] for i in range(N)]

or

demod4 = [[0 for i in range(M)]*N]

Or try using numpy.

import numpy as np

N, M = 100, 5000
np.zeros((N, M))