Re: [boost] [range] Best way to count the elements in a filtered range?

Subject: Re: [boost] [range] Best way to count the elements in a filtered range?
From: Gonzalo Brito Gadeschi (g.brito_at_[hidden])
Date: 2013-06-19 11:13:41

>
> Try boost::distance(rng | filtered(pred)).

Distance works as expected, thanks!

On Wed, Jun 19, 2013 at 5:03 PM, Nathan Crookston <
nathan.crookston_at_[hidden]> wrote:

> Hi Gonzalo,
>
> Gonzalo Brito Gadeschi wrote:
>
> > Someone suggested to use boost::size in the other thread, but size does
> >
> > boost::end(rng) - boost::begin(rng)
> >
> > which is not the number of elements in the filtered range.
> >
>
> Try boost::distance(rng | filtered(pred)).  Size shouldn't even compile,
> since it requires random access, and a filtered range cannot be random
> access.
>
> HTH,
> Nate
>
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