[WORK] groupBy is in! Next: aggregate

[Andrei Alexandrescu via Digitalmars-d]

On 1/23/15 1:56 PM, MattCoder wrote:
> 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).

Yah, that would be partition(). -- Andrei