Better way to append to array than ~= ?

[Vladimirs Nordholm]

On Tuesday, 3 April 2018 at 20:41:01 UTC, Alex wrote:
> On Tuesday, 3 April 2018 at 20:02:46 UTC, Vladimirs Nordholm 
> wrote:
>> On Tuesday, 3 April 2018 at 19:53:11 UTC, Meta wrote:
>>> [...]
>>
>> I don't think I know the size of the arguments.
>>
>> If I pass in "123" and MySpecialType('a'), the result should 
>> be:
>>
>>     assert(foo("123", MySpecialType('a')) == 
>> [MySpecialType('1'), MySpecialType('2'), MySpecialType('3'), 
>> MySpecialType('a')]);
>>
>> What should the length of the pre-allocated array be?
>
> In my try, I iterate the args twice. The first time to 
> calculate the number of elements, then preallocate and then 
> iterate them again and constructing the proper objects.
>
> It is not nice, but about 1/3 of time, compared to original 
> version, compiled in release mode.
>
> https://run.dlang.io/is/E6ckog

Yeah, I will probably need to iterate twice.

Thanks a bunch 👍