CODEWITHSUNDEEP
python
Nae
Nae

Reputation: 19

Finding prime numbers in python : why the output starts with 2

for num in range(2,101):
    for i in range(2,num):
        if (num % i) == 0:
            break  
    else :
        print(num, end = ' ')

I don't understand why the output starts from 2

I thought num starts with 2, and the i also starts with 2

so, (num % i) == 0 is right

What's wrong with me?

Upvotes: 0

Views: 39

Answers (1)

Barmar
Barmar

Reputation: 781616

When num == 2, range(2, num) is empty, because ranges stop before the end number.

So for i in range(2, num): never executes the body in that case, and therefore it never tests num % i == 0. The loop ends immediately, without executing break, so it goes into the else: block.

Upvotes: 3

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