関連ワード:  how to initialise a matrix in python    how to declare a matrix in python    how to initialize a matrix in python using numpy    how to init matrix in python    how to initialize a 2d matrix in python    how to declare a 2d matrix in python    how to declare a empty matrix in python    how to initialize a 3x3 matrix in python    how to initialize a matrix with 0 in python    how to initialize empty matrix in python