関連ワード:  how to make a zero vector in python    how to make a zero matrix in python    how to make a zero array in python    how to make a empty array in python    how to make a empty matrix in python    how to create a 0 matrix in python    how to make an empty vector in python    how to make an empty array in python numpy    how to create a 2d empty array in python    how to create a new empty array in python