On Wed, Nov 27, 2013 at 11:08 AM, Rafael Knuth <rafael.kn...@gmail.com>wrote:
> Hej there, > > I am trying to figure out how exactly variables in nested loops are > generated, and don't get it 100% right yet. Here's my code: > > for n in range(2, 10): > for x in range(2, n): > if n % x == 0: > print(n, 'equals', x, '*', n//x) > break > else: > print(n, 'is a prime number') > > And here's what I assume happens inside these for loops: > > #1 Round: > n = 2 > x = no result > >>> > 2 is a prime number > > #2 Round: > n = 3 > x = 2 > >>> > 3 is a prime number > > #3 Round: > n = 4 > x = 3 > >>> > Round 3 would be n = 4, x = 2. The inner loop starts from its own beginning (x = 2) and repeats as often as necessary to get the break condition or complete to the x = n condition > My assumption about the way these two for loops work is wrong, because > the output cannot be "4 is a prime number" for obvious reasons. > > Can anyone help me understand? > I am using Python 3.3.0. Thank you! > > All the best, > > Raf > I copied your code into a python 2.7 shell and got this: >>> for n in range(2, 10): ... for x in range(2, n): ... if n % x == 0: ... print(n, 'equals', x, '*', n//x) ... break ... else: ... print(n, 'is a prime number') ... (2, 'is a prime number') (3, 'is a prime number') (4, 'equals', 2, '*', 2) (5, 'is a prime number') (6, 'equals', 2, '*', 3) (7, 'is a prime number') (8, 'equals', 2, '*', 4) (9, 'equals', 3, '*', 3) What exactly do you get when you run the code? Since print is a function in python 3, my output will look slightly different than yours > _______________________________________________ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > https://mail.python.org/mailman/listinfo/tutor > -- Joel Goldstick http://joelgoldstick.com
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