2.2 features

[Tom Good]

cjc26 at nospam.cornell.edu (Cliff Crawford) wrote in message news:<pRW77.126602$EF2.17425212 at typhoon.nyroc.rr.com>...
> * Tom Good <Tom_Good1 at excite.com> menulis:
> | 
> | #------ begin code
> | 
> | def genWhile(g, condition):
> |     """
> |     run generator g while 'condition' is true.
> |     Condition is a partial expression string such as "< 10"
> |     to be evaluated with g.next() as the left side
> |     """
> |     while 1:
> |         next = g.next()
> |         if eval("next " + condition):
> |             yield next
> |         else:
> |             raise StopIteration
> | 
> | #------ end code
> | 
> | Then you can say, for example:
> | 
> | >>> g = fib()
> | >>> [x for x in genWhile(g, "< 50")]
> | 
> | [1, 1, 2, 3, 5, 8, 13, 21, 34]
> | 
> | ...to get the Fibonacci numbers that are less than 50.
> 
> This is neat, but I think passing in a function to test the condition
> would be cleaner than passing in a string.  Like this:
> 
> def genWhile(g, condition):
>     while 1:
>         next = g.next()
>         if condition(next):
>             yield next
>         else:
>             return
> 
> [x for x in genWhile(fib(), lambda f: f < 50)]

You are right, that is a good way!  I wrote the string based version,
then thought of that solution afterwards.


Tom