2D list divided by another 2D list-CodePudding

I have two 2-D list:

A = [[10,20,30],
     [5,8,10]]

B = [[1,2,5],
     [5,4,2]]

The output should be:

result = [[10,10,6],
          [1,2,5]]

What is the most efficient way to achieve this? I could only think of nested for loop which is pretty complicated...

CodePudding user response：

You mentioned the tag numpy, then use it.

If they're not already numpy arrays, first convert them:

A = np.array(A)
B = np.array(B)

Then divide them:

>>> A / B
array([[10., 10.,  6.],
       [ 1.,  2.,  5.]])
>>>

As @sj95126 mentioned, to make it integer type values and a list, use:

>>> (A / B).astype(int).tolist()
[[10, 10, 6], [1, 2, 5]]
>>>

Or as @wjandrea mentioned, you could make them integers already in the beginning:

A = np.array(A, dtype='int')
B = np.array(B, dtype='int')

Then do:

>>> (A // B).tolist()
[[10, 10, 6], [1, 2, 5]]
>>>

CodePudding user response：

You can use np.floor_divide, which is equivalent to // and converts its inputs to arrays automatically:

>>> np.floor_divide(A, B)
array([[10, 10,  6],
       [ 1,  2,  5]])

A list comprehension would be a non-numpy solution free of libraries:

>>> [[a // b for a, b in zip(*rows)] for rows in zip(A, B)]
[[10, 10, 6], [1, 2, 5]]