Matlab to Python Matrix Code

Question

I am trying to translate some code from MATLAB to Python. I have been stumped on this part of the MATLAB code:

[L,N] = size(Y);
if (L<p)
    error('Insufficient number of columns in y');
end

I understand that [L,N] = size(Y) returns the number of rows and columns when Y is a matrix. However I have limited experience with Python and thus cannot understand how to do the same with Python. This also is part of the reason I do not understand how the MATLAB logic with in the loop can be also fulfilled in Python.

Thank you in advance!

Also, in case the rest of the code is also needed. Here it is.

function [M,Up,my,sing_values] = mvsa(Y,p,varargin)

if (nargin-length(varargin)) ~= 2
    error('Wrong number of required parameters');
end

% data set size
[L,N] = size(Y)

if (L<p)
    error('Insufficient number of columns in y');
end

Answer 1

I am still unclear as to what p is from your post, however the excerpt below effectively performs the same task as your MATLAB code in Python. Using numpy, you can represent a matrix as an array of arrays and then call .shape to return the number of rows and columns, respectively.

import numpy as np

p = 2
Y = np.matrix([[1, 1, 1, 1],[2, 2, 2, 2],[3, 3, 3, 3]])

L, N = Y.shape
if L < p:
    print('Insufficient number of columns in y')