如何检查矩阵是否在矩阵列表中 Python

Question

This is the list of matrices;

[matrix([[1, 0],
         [1, 0],
         [1, 0],
         [1, 0]]),
 matrix([[0, 0, 0, 0],
         [1, 1, 1, 1]]),
 matrix([[0, 1],
         [0, 1],
         [0, 1],
         [0, 1]]),
 matrix([[0, 0, 0, 0],
         [1, 1, 1, 1]]),
 matrix([[1, 1, 1, 1],
         [0, 0, 0, 0]])]

and I want to check if a matrix is already inside the list example;

a = matrix([[0, 0, 0, 1],
            [1, 1, 1, 0]])

So if a is in m then print True else print False

Answer 1

I assume you are using NumPy. If this is the case, don't use np.matrix , use np.array . np.matrix exists almost exclusively for legacy reasons and has undesirable features.

You can use any with a generator comprehension and np.array_equal . This will short-circuit to True if the array is found in the input list, otherwise return False .

import numpy as np

L = [np.array([[1, 0], [1, 0], [1, 0], [1, 0]]),
     np.array([[0, 0, 0, 0], [1, 1, 1, 1]]),
     np.array([[0, 1], [0, 1], [0, 1], [0, 1]]),
     np.array([[0, 0, 0, 0], [1, 1, 1, 1]]),
     np.array([[1, 1, 1, 1], [0, 0, 0, 0]])]

A = np.array([[0, 0, 0, 1], [1, 1, 1, 0]])

res = any(np.array_equal(A, i) for i in L)  # False