Seed Value for reduce function
Vino
vino.bheeman at hotmail.com
Mon Dec 11 11:59:05 UTC 2017
On Sunday, 10 December 2017 at 06:01:49 UTC, Ali Çehreli wrote:
> On 12/09/2017 06:19 PM, Vino wrote:
>
>> [...]
>
> When no seed value is specified, fold (and reduce) take the
> first element as the seed. When the range is empty, then there
> is a run-time failure:
>
> object.Exception@/usr/include/dmd/phobos/std/algorithm/iteration.d(2794): Cannot reduce an empty input range w/o an explicit seed value.
>
> The solution is to provide an explicit seed value:
>
> import std.container;
> import std.file;
> import std.algorithm;
>
> void main() {
> const d = "/tmp/empty_folder";
> const Size = 42;
> auto SdFiles = Array!ulong(dirEntries(d,
> SpanMode.depth).map!(a => a.size).fold!((a,b) => a +
> b)(size_t(0)))[].filter!(a => a > Size);
> }
>
> I chose size_t(0) but you can use a variable, size_t.init, etc.
>
> Ali
Hi Ali,
Thank you very much, was able to apply your logic which resolved
the issue.
From,
Vino.B
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