Simple if-else question

Tue Sep 29 12:09:50 EDT 2009

Sandy wrote:
> Hi all,
> A simple and silly if-else question.
> I saw some code that has the following structure. My question is why
> else is used there though removing else
> has the same result. More important, is it not syntactically wrong :-(
>> for i in xrange(8):
> if i < 4:
> print i
> else:
> print i
>> Cheers,
> dksr

The else is not tied to the if, it is tied to the for. The statements 
in a for-else (and while-else, and if-else) only execute if the control 
expression becomes False. If you want to avoid executing the else 
clause, you have to break out of the loop.
Some examples:
In [1]: for i in xrange(8):
 ...: if i < 4:
 ...: print i
 ...:
0
1
2
3
In [2]: for i in xrange(8):
 ...: if i < 4:
 ...: print i
 ...: else:
 ...: print i
 ...:
0
1
2
3
7
In [3]: for i in xrange(8):
 ...: if i < 4:
 ...: print i
 ...: if i == 1:
 ...: break
 ...: else:
 ...: print i
 ...:
0
1
Hope this helps!
~Ethan~