Python: Multiply elements with eachother in a list-CodePudding

How can I multiply every element in a list with every other element in the list by using a for loop? Like this: [1, 3, 5, 7] should be multiplied like this: 1 * 3 1 * 5 1 * 7 3 * 5 3 * 7 5 * 7

CodePudding user response：

Sure you can:

a = [1, 3, 5, 7]
s = 0
for i in range(len(a)):
    for j in range(i   1, len(a)): 
        s  = a[i] * a[j]
print(s)

CodePudding user response：

You can multiply together each combination generated by combinations and sum them.

from itertools import combinations
from operator import mul
l = [1, 3, 5, 7]

sum([mul(*x) for x in combinations(l,2)])

Output

CodePudding user response：

Use 2 loops to get the combinations of the list elements. Multiply the list elements then add them.

l = [1, 3, 5, 7]
sum = 0

for i in range(len(l)):
    for j in range(i 1, len(l)):
      sum  = l[i]*l[j]