• Edwin van Leeuwen (6/6) Apr 10 2014 I'd like to filter a range and then change the filtered results,
• bearophile (7/12) Apr 10 2014 Mixing functional-style programming with mutation is a source of
• monarch_dodra (16/22) Apr 10 2014 It doesn't. It returns front, and by Ref if at all possible too.

"Edwin van Leeuwen" <edder tkwsping.nl> writes:

I'd like to filter a range and then change the filtered results, 
but FilterResult returns a const. Is there any (straightforward) 
way of doing what I want?

I guess I could create duplicates, but I would like my changes 
also to be reflected in the original range.

Cheers, Edwin

"bearophile" <bearophileHUGS lycos.com> writes:

Edwin van Leeuwen:

 I'd like to filter a range and then change the filtered 
 results, but FilterResult returns a const. Is there any 
 (straightforward) way of doing what I want?

 I guess I could create duplicates, but I would like my changes 
 also to be reflected in the original range.

Mixing functional-style programming with mutation is a source of 
troubles. If you want to do that it's safer and more clear to use 
normal imperative code. (There is also the copy() function, but I 
think it doesn't help you in this case).

Bye,
bearophile

"monarch_dodra" <monarchdodra gmail.com> writes:

On Thursday, 10 April 2014 at 10:30:19 UTC, Edwin van Leeuwen 
wrote:
 I'd like to filter a range and then change the filtered 
 results, but FilterResult returns a const. Is there any 
 (straightforward) way of doing what I want?

 I guess I could create duplicates, but I would like my changes 
 also to be reflected in the original range.

 Cheers, Edwin

It doesn't. It returns front, and by Ref if at all possible too.

//----
void main()
{
     auto arr = iota(0, 10).array();
     foreach (ref e; arr.filter!"a%2"())
         --e;
     writeln(arr); //duplicate evens
}
//----
[0, 0, 2, 2, 4, 4, 6, 6, 8, 8]
//----

There must be something else that is wrong. What are you trying 
to do?