関連ワード:  sum of 2d array in python    addition of 2d array in python    sum of 2d array python numpy    sum of each row in 2d array in python    how to find sum of 2d array in python    sum of rows and columns in 2d array in python    sum of elements in 2d array python    sum of column in 2d array python    sum over 2d array python    sum of all elements in 2d array python