From: timr <timrandg@...>
Date: 2010-08-28T13:40:08+09:00
Subject: Re: how about Array#collect_until

> I would rather place this code in Enumerable.  Then all other classes
> mixing in this module will benefit.
>

Good idea.


> >    def collect_until(fn,&block)
> >      results = []
> >      self.each do |x|
>
> Why does everybody write "self.each" when "each" is sufficient?

self.sorry, er, I mean sorry. No you're right. It is overly explicit.

>
> >        result = (yield x)
> >        results<<  result
> >        break if fn.call(result)
>
> As far as I can see this is not in line with your original requirement
> because in your original posting you evaluated the termination condition
> on the original value while this code does it on the result of the
> mapping calculation.

From the original posting:
[1,2,3].collect_until({|x| x%2 == 0}) {|item| item + 10} # => [11,12]
To get this to work the result from the yield to {|item| item + 10}
block would be run through the {|x| x%2 == 0} block to check if we
are
done.

So, I was shooting for a method that would send to block, take the
result and check it against fn and quit if condition was met. With the
call made as [].collect_until(fn,&block). I am trying to save
processing from sending any more items than are required to a
calculation intensive block.

The other tests may help clarify the expected behavior. In each case
the method should result in a collection that DOES NOT INCLUDE A
RESULT FOR EVERY ITEM in the original set since the condition is met
part way through and break is executed. Therefore, it provides the
most a collection of calculations upto and including the solution when
an end condition was met.

> > p %w[ find out if that  this  but not the other mother
> > mouth].collect_until(lambda {|word| word[-2,2] == 'st' }){|item| item
> > + "t" }
>
> > puts "another attempt"
>
> > p [1,6,7,5,3,0,10,12,14].collect_until(Proc.new {|num| num>  25 }){|
> > item| item * 4 }
>
> > puts "another attempt"
> > p [1,2,3].collect_until(Proc.new {|x| x%2 == 0}) {|item| item + 10}
>
> Kind regards
>
>         robert
>
> --
> remember.guy do |as, often| as.you_can - without endhttp://blog.rubybestpractices.com/