関連ワード:  how to make 2d list in python    how to make 2 dimensional list in python    how to create 2d list in python    how to declare 2d list in python    how to do 2d list in python    how to make empty 2d list in python    how to declare empty 2d list in python    how to get size of 2d list in python    how to get length of 2d list in python    how to make 2d list to 1d list python