We have slices, do we have Strides?

[Kai Meyer]

On 08/08/2011 05:25 PM, Steven Schveighoffer wrote:
> On Mon, 08 Aug 2011 18:33:55 -0400, Kai Meyer <kai at unixlords.com> wrote:
>
>> On 08/08/2011 12:55 PM, Jonathan M Davis wrote:
>>>> I have a problem I'd really like to use Strides for to simplify my
>>>> code.
>>>> Currently, I do this:
>>>> foreach(n; 0..chunks)
>>>> comp_arr[n] = values[(n * step_size) + n]
>>>> if(!all_same(comp_arr, comp_arr[0]))
>>>>
>>>> It would eliminate an entire 2 lines of code for each time I want
>>>> strides, to be able to do this:
>>>> if(!all_same(bytes[i..$..step_size])
>>>>
>>>> Meaning, start with i, grab all elements at i + block_size * n until
>>>> block_size * n> bytes.length. Right?
>>>>
>>>> -Kai Meyer
>>>
>>> Would std.range.stride work for you?
>>>
>>> - Jonathan M Davis
>>
>> It would, if there was a way to give it an offset:
>>
>> int[] a = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ];
>
> fixed:
>
>> assert(equal(stride(a, 3), [ 1, 4, 7, 10 ][]));
>> assert(equal(stride(a[1..$], 3), [ 2, 5, 8, 11 ][]));
>> assert(equal(stride(a[2..$], 3), [ 3, 6, 9 ][]));
>> assert(equal(stride(a[3..$], 3), [ 4, 7, 10 ][]));
>
> -Steve

Awesome :) Thanks Steve!