Get the (multiplicative) product of a tuple or list?

Question

Let's say I have a

class Rectangle(object):                                               
def __init__(self, length, width, height=0):                                                   
    self.l = length                                               
    self.w = width                                                
    self.h = height                                               
    if not self.h:                                                     
        self.a = self.l * self.w                                       
    else:                                                              
        from itertools import combinations                            
        args = [self.l, self.w, self.h]                                
        self.a = sum(x*y for x,y in combinations(args, 2)) * 2
                 # original code:
                 # (self.l * self.w * 2) + \                            
                 # (self.l * self.h * 2) + \                            
                 # (self.w * self.h * 2)                                
        self.v = self.l * self.w * self.h                                           

What's everyone's take on line 12?

self.a = sum(x*y for x,y in combinations(args, 2)) * 2 

I've heard that explicit list index references should be avoided.

Is there a function I can use that acts like sum(), but only for multiplication?

Thanks for the help everyone.

Answer 1

In short, just use np.prod

import numpy as np
my_tuple = (2, 3, 10)
print(np.prod(my_tuple))  # 60

Which is in your use case

np.sum(np.prod(x) for x in combinations(args, 2))

np.prod can take both lists and tuple as a parameter. It returns the product you want.