A simple question about loops in Python

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I've tried two loops samples but ı didint understand why when"loop1" starts from "3", "loop2" starts from "2"? ı supposed that both should have been the same.

Here is the output:

3 prime
4 = 2 * 2.0
5 prime
2 prime
3 prime
4 = 2 * 2.0
5 prime

What I have tried:

Python

<pre lang="Python">

def loop1():
    for n in range (2,6):
        for x in range(2,n):
            if n % x==0:
                print(n,"=",x,"*",n/x)
            else:
                print(n,"prime")

            break
loop1()

def loop2():
    for c in range (2,6):
        for k in range(2,c):
            if c % k==0:
                print(c,"=",k,"*",c/k)
                break
        else:
                print(c,"prime")
loop2()

Posted 4-Dec-18 1:44am

bswarrior

Updated 4-Dec-18 2:58am

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Richard MacCutchan · Accepted Answer · 2018-12-04T02:59:00

The second loop tries to repeat for the range (2,2) in the first iteration. Which is effectively while x is greater than 2 and less than 2: but that is impossible so the loop terminates. So the output starts at 3 which is the next iteration of the outer loop when n has a value of 3.

If you look at the output from the second loop you can see the first line output is :

2 prime

But you know that 2 is not a prime so how did that happen? Simply because your else clause is only indented once so it belongs to the preceding for statement rather than the if.