How to divide list item by list item from another list using Python?

Question

I would like to divide list items inside two lists.

a = [[1, 0, 2], [0, 0, 0], [1], [1]]
b = [[5, 6, 4], [6, 6, 6], [3], [3]]

How can I divide a by b to obtain this output:

c = [[0.2, 0, 0.5], [0, 0, 0], [0.333], [0.333]]

Can anyone help me?

Answer 1

Using itertools.izip (Python2.7):

import itertools

[[float(aaa) / bbb for (aaa, bbb) in itertools.izip(aa, bb)] \
    for (aa, bb) in itertools.izip(a, b)]

Answer 2

Zip the two lists and use a list comprehension:

from __future__ import division   # in python2 only
result = [[x/y for x,y in zip(xs, ys)] for xs, ys in zip(a, b)]

---

Sample run:

In [1]: a = [[1, 0, 2], [0, 0, 0], [1], [1]]
   ...: b = [[5, 6, 4], [6, 6, 6], [3], [3]]
   ...: 

In [2]: result = [[x/y for x,y in zip(xs, ys)] for xs, ys in zip(a, b)]

In [3]: result
Out[3]: [[0.2, 0.0, 0.5], [0.0, 0.0, 0.0], [0.3333333333333333], [0.3333333333333333]]

Answer 3

from __future__ import division # for Python2

[[x / y for x, y  in zip(*item)] for item in zip(a, b)]