Python dot-multiply lists on list of lists, without using numpy

Question

I am quite new to python and getting my head around arrays as such, and I am struck on a rather simple problem. I have a list of list, like so:

a = [[1,0,1,0,1],[0,0,1,0,1],[0,0,1,0,1],[1,1,1,0,1],[1,0,0,0,0]]

and I would like to multiply elements of each list with each other. Something like:

a_dot = [1,0,1,0,1]*[0,0,1,0,1]*[0,0,1,0,1]*[1,1,1,0,1]*[1,0,1,0,0]
=[0,0,1,0,0]

Was wondering if I can do the above without using numpy/scipy.

Thanks.

Answer 1

import operator
a_dot = [reduce(operator.mul, col, 1) for col in zip(*a)]

But if all your data is 0s and 1s:

a_dot = [all(col) for col in zip(*a)]

Answer 2

Did you try the reduce function? You call it with a function (see it as your operator) and a list and it applies it the way you described.

Answer 3

You can solve by below code,

def multiply(list_a,list_b):
    c = []
    for x,y in zip(list_a,list_b):
        c.append(x*y)
    return c

reduce(lambda list_a,list_b: multiply(list_a,list_b), a)

Happy coding!!!!