dict.items() vs dict.iteritems and similar questions

[Laurent Pointal]

Drew a écrit :
> When is it appropriate to use dict.items() vs dict.iteritems. Both
> seem to work for something like:
> 
> for key,val in mydict.items():
>   print key,val
> 
> for key,val in mydict.iteritems():
>   print key,val
> 
> Also, when is it appropriate to use range() vs xrange(). From my
> understanding, xrange() essentially gives you an iterator across a
> range, so it should be used when iterating. Should you only use
> range() when want to physically store the range as a list?

iteritems and xrange only provide values when requested.
items and range build complete list when called.

Both work, you may prefer xrange/iteritems for iteration on large
collections, you may prefer range/items when processing of the result
value explicitly need a list (ex. calculate its length) or when you are
going to manipulate the original container in the loop.

A+

Laurent.