Cannot reduce an empty iterable w/o an explicit seed value

[Vino]

On Thursday, 9 November 2017 at 13:24:45 UTC, Nicholas Wilson 
wrote:
> On Thursday, 9 November 2017 at 12:40:49 UTC, Vino wrote:
>> [...]
>
> The problem is
> subdirTotalGB = ((reduce!((a,b) => a + b)(SdFiles)) / 1024 / 
> 1024 / 1024);
> with reduce you need to give it a seed (an initial value to 
> start with).
> See
> https://dlang.org/phobos/std_algorithm_iteration.html#.reduce
>
>> [...]
>
> To your actual use case, you can do:
>
> foreach (d; parallel(dFiles[], 1)) {
> float subdirTotalGB = dirEntries(join(["\\\\?\\", d]), 
> SpanMode.depth)
>     .filter!(a => a.isFile))
>     .map!(a => to!float(a.size)))
>     .fold!((a, b) => a + b)(0) // Provide an explicit seed.
>
>     if (subdirTotalGB > SizeDir) {
>         Result.insertBack(d);
>         Result.insertBack(to!string(subdirTotalGB));
>     }
> }

Hi,

  Thank you very much and I wanted to use reduce function instead 
of fold for accuracy purpose so i just added the below line and 
it worked.

Code:
float x;
x = 0;
{subdirTotalGB = ((reduce!((a,b) => a + b)(x, SdFiles)) / 1024 / 
1024 / 1024);}