CODEWITHSUNDEEP
pythonpython-3.x
aBOREDguy
aBOREDguy

Reputation: 21

display prime numbers with upper and lower limit using iterators (not generator)

I get the values but it also prints 'None' for non prime values

class Prime:
    def __init__(self, n1, n2):
        self.n1 = n1
        self.n2 = n2

    def __iter__(self):
        return self

    def __next__(self):
        num = self.n1
        self.n1 += 1
        for x in range(2, num):
            if num % x == 0:
                break
        else:
            return num


z = Prime(30, 200)
for k in z:
    print(k)

results: None 31 None None None None None 37 None None None 41 None 43

Upvotes: 0

Views: 88

Answers (1)

mario_sunny
mario_sunny

Reputation: 1432

If a break is encounted in a for/else loop in Python, the else block is never executed. Hence, None is returned by default. That is almost certainly the root cause of your error.

Your function should probably look like this:

    def __next__(self):
        num = self.n1
        self.n1 += 1
        for x in range(2, num):
            if num % x == 0:
                break
        return num

(Although now that I look at it, that for loop should probably be a while loop, I am not sure your logic is correct here)

for/else reference

Upvotes: 2

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