I want a list of all the prime numbers that are smaller than a integer

Question

Hey so i have these two functions. The first one checks whether a number is a prime number which works. The second one is supposed to take a number and have all the prime numbers that are smaller than that number added into a sorted list. This is the code i have right now,

def is_prime(n):
    flag = True
    if n == 1:
        flag = False
    for i in range(2, n):
        if (n % i) == 0:
            flag = False
    return flag


def primes(num):
    primelist = []
    flag = is_prime(num)
    for i in range(1, num - 1):
        if flag == True:
            primelist.append(num)
    return sorted(primelist)

How would i go about adding all the prime numbers lower than a integer into the list?

Answer 1

You've almost got it!

The issue in your primes function is that flag is computed outside of the loop. So it's computed only once for the input num .

Instead, it should be computed for every loop entry.