Casting MapResult

[Ali Çehreli via Digitalmars-d-learn]

On 06/15/2015 08:21 AM, Adam D. Ruppe wrote:

 > don't call .array if you don't have to, chaining calls to
 > map and such, even foreach(item; some_map_result) can be done without
 > actually building the array and can give more efficiency.

To add, the OP can use 'sum' or 'reduce' for "adding them together":

   http://dlang.org/phobos/std_algorithm_iteration.html

import std.stdio;
import std.algorithm;
import std.math;

void main()
{
     float[] arr = [ 1.5, 2.5 ];
     auto y = arr.map!exp;
     writeln(y.sum);    // same as sum(y)
}

An equivalent of the last line:

     writeln(reduce!((result, a) => result + a)(y));

Ali