On Jul 2, 2009, at 7:45 AM, Robert Klemme wrote:

>  2009/7/2 Bil Kleb <Bil.Kleb@[...].gov>:
> > Hi,
> >
> > Given an array of integers, I need to delete all those
> > entries that are lower than the current array index.
> >
> > I first thought of the non-existent,
> >
> >  array.delete_if_with_index{ |e,i| e < i }
> >
> > then,
> >
> >  remove_indices = []
> >  array.each_with_index{ |e,i| remove_indices << i if e < i }
> >  array.delete_at( remove_indices )
> >
> > or the same, but with a fictious inject_with_index,
> >
> >  remove_indices = inject_with_index([]){|acc,e,i| acc << i if e < i }
> >  array.delete_at( remove_indices )
> >
> > and finally the 1.9 possibility,
> >
> >  array.map_with_index!{ |e,i| e < i ? nil : e }.compact!
> >
> > before compromising with
> >
> >  array = (0...array.size).zip(array).map{ |i,e| e < i ? nil :  
> > e }.compact
> >
> > Anything more elegant available?
> >
> > Or perhaps an alternative way to attack the problem?
> 
>  irb(main):010:0> a = %w{foo bar baz}
>  => ["foo", "bar", "baz"]
>  irb(main):011:0> current = 1
>  => 1
>  irb(main):012:0> a.slice! 0...current
>  => ["foo"]
>  irb(main):013:0> a
>  => ["bar", "baz"]

You need to reread what Bil was asking for.  ;)

James Edward Gray II