从矩阵列表中删除重复矩阵

def is_equal(matrix1, matrix2):
    if len(matrix1) != len(matrix2) or len(matrix1[0]) != len(matrix2[0]):
        return False
    for i in range(len(matrix1)):
        for j in range(len(matrix1[0])):
            if matrix1[i][j] != matrix2[i][j]:
                return False
    return True

def remove_duplicates(matrix_list):
    unique_matrices = []
    matrix_set = set()
    for matrix in matrix_list:
        if str(matrix) not in matrix_set:
            matrix_set.add(str(matrix))
            unique_matrices.append(matrix)
    return unique_matrices

# 示例用法
matrix_list = [[1, 2, 3], [4, 5, 6], [1, 2, 3], [7, 8, 9]]
unique_matrices = remove_duplicates(matrix_list)
print(unique_matrices)