Project Euler - Problem #1 - Multiples of 3 or 5 - Python

Question

This is my solution for problem 1 of the projectEuler with python:

import time
start_time = time.time()   #Time at the start of program execution

def multiple_3_or_5(n):
    if n % 3 ==0 or n % 5 ==0:
        return True
    else:
        return False

sum = 0
for i in range (1,1000):
    # print ("checking :" , i)
    if multiple_3_or_5(i):
        # print ("multiple is fine for", i)
        sum = sum + i
        # print ("Sum is =", sum)

print (sum)

end_time = time.time()   #Time at the end of execution
print ("Time of program execution:", (end_time - start_time))   #Time of program execution

Answer 1

Put all of your code in functions. Including the code to represent Euler problem 1, along with the code to exercise that function.

Implement automated tests for those functions. While implementing such code, express your expections for correctness in the form of automated tests. Ultimately, you'll want to learn how to use one of Python's testing frameworks, such as pytest. In the meantime, or in small-scale or informal situations, you can roll your own testing code, as illustrated below.

Functions based on a simple boolean test can return directly. You can drop the if-else clauses from multiple_3_or_5() and just return the boolean result.

The built-in sum function takes an iterable. Just add up the values of i for which multiple_3_or_5(i) returns true.

Don't obsess over performance until you know you have a problem. This program is uninteresting from a performance perspective. Drop the extraneous timing code. And even if you disagree with my perspective, at least focus your measurements on the relevant code -- just the call of euler_1() function, rather than the execution of the entire program.

def main():
    TESTS = (
        (10, 23),
        (1000, 233168),
    )
    for limit, expected in TESTS:
        got = euler_1(limit)
        if got == expected:
            print('ok')
        else:
            print(limit, got, expected)

def euler_1(limit = 1000):
    return sum(i for i in range (1, limit) if multiple_3_or_5(i))

def multiple_3_or_5(n):
    return n % 3 == 0 or n % 5 == 0

if __name__ == '__main__':
    main()