need help on generator...

[Craig Ringer]

On Fri, 2005-01-21 at 16:54 +0100, Francis Girard wrote:

> First, I think that you mean :
> 
> consecutive_sets = [ x[offset:offset+subset_size]
>                       for subset_size in xrange(2, len(x))
>                       for offset in xrange(0, len(x) + 1 - subset_size)]
> 
> (with square brackets).

> I'm just trying to understand and obviously I'm missing the point.

Yep. This:

( x for x in xrange(10) )

will return a generator that calculates things as it goes, while this:

[ x for x in xrange(10) ]

will return a list. 

Check out:
	http://www.python.org/peps/pep-0289.html
	http://docs.python.org/whatsnew/node4.html
	http://www.python.org/dev/doc/newstyle/ref/genexpr.html
for details.

--
Craig Ringer