CODEWITHSUNDEEP
pythoncomputationdot-productmathematical-expressions
AJW
AJW

Reputation: 5873

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

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.

Upvotes: 1

Views: 1043

Answers (3)

Yuv
Yuv

Reputation: 202

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!!!!

Upvotes: 0

Eric
Eric

Reputation: 97631

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)]

Upvotes: 6

user189
user189

Reputation: 604

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.

Upvotes: 0

Related Questions