Problem from CodeWars It returns 5 instead of 23 . Can someone help me understand my code?

Question

Problem :

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Finish the solution so that it return s the sum of all the multiples of 3 or 5 below the number passed in.

Note : If the number is a multiple of both 3 and 5, only count it once.

Code :

def solution(number): 
    return sum( (i%3==0 or i%5==0) for i in range (number))

solution(10)

Answer 1

The problem asks you to sum the numbers which are multiples of 3 or 5, but here you're summing the result of (i%3==0 or i%5==0) , which is a boolean (which in Python is equal to the integers 0 and 1).

Meaning you're just counting the number of multiples of 3 and 5, not summing them. This can trivially be checked by just running the function locally in a Python shell: you'll get 5 (because range starts at 0 inclusive, so while 0 does not matter to the sum it matters to the counting).

A generator comprension is "value returned [for] value [in] producer [if] condition". Your test needs to go at the end, as a condition.

Answer 2

Basically you are summing the boolean values that's why your answer is not correct please try following code

Code:

def solution(number): 
    return sum( i for i in range (number) if (i%3==0 or i%5==0))

solution(10)

Answer 3

In each iteration of the loop, you are evaluating the condition

(i%3==0 or i%5==0)

which is True exactly five times when number is 10. Each True counts as a 1 , hence you get 5 for the sum.

To get the correct answer, you need to rearrange the statement so that you evaluate i whenever your condition is true. For more details, see list comprehensions .