[WORK] groupBy is in! Next: aggregate

[MattCoder via Digitalmars-d]

On Friday, 23 January 2015 at 18:08:30 UTC, Andrei Alexandrescu 
wrote:
> So H.S. Teoh awesomely took 
> https://github.com/D-Programming-Language/phobos/pull/2878 to 
> completion. We now have a working and fast relational "group 
> by" facility.
>
> See it at work!
>
> ----
> #!/usr/bin/rdmd
>
> void main()
> {
>     import std.algorithm, std.stdio;
>     [293, 453, 600, 929, 339, 812, 222, 680, 529, 768]
>         .groupBy!(a => a & 1)
>         .writeln;
> }
> ----
>
> [[293, 453], [600], [929, 339], [812, 222, 680], [529], [768]]

Sorry if this a dumb question, but since you're grouping an array 
according some rule, this shouldn't be:

[293, 453, 929, 339, 529][600, 812, 222, 680, 768]

?

Because then you have the array of "trues" and "falses" according 
the condition (a & 1).

Matheus.