Thanks, Jesse! Your solution looks fine. I'll study the words 'keep' and
'reduce' so I can understand the magic involved. ;-)
There may be a more direct way to do this. Maybe some recursive method?
As you may have seen, if the initial sequence is
{ 0 1 2 3 4 5 6 7 8 9 }, then the result will be
{ 0 2 4 6 8 1 5 9 7 3 }. As I'm going to apply the move-core-to-end on
that, over and over, I could use the first result as a permutation
sequence with Daniel Ehrenberg's map-permutation word.
/Jon
On 2/25/09 1:11 PM, Jesse Rusak wrote:
> How about this?
>
> : move-core-to-end ( seq -- seq )
> [ length 2 - [1,b] ] keep [ swap move-to-end ] reduce ;
>
> Though I feel like there's probably a more direct way to do this than
> moving each element in turn.
>
> - Jesse
>
> On 25-Feb-09, at 4:30 AM, Jon Kleiser wrote:
>
>> Here's follow-up to my first question about how to move the nth
>> element
>> to the end, which Daniel and Slava had several solutions for.
>>
>> On 2/23/09 7:19 PM, Daniel Ehrenberg wrote:
>>> Well, here's an inefficient way to do it, but the code is pretty:
>>>
>>> : move-to-end ( n seq -- newseq )
>>> [ remove-nth ] [ nth ] 2bi suffix ;
>> I now wanted to apply that operation for n=1 to n=length-2, i.e.
>> skipping the first (0) and last (length-1) index. I came up with the
>> following solution, but I suspect Daniel, Slava, or other Factor heads
>> on this list, may have a better (looking) way of doing it, maybe
>> without
>> the variable. Here's mine:
>>
>> : move-core-to-end ( seq -- seq )
>> SYMBOL: target
>> dup
>> target set
>> length 2 - [1,b] [ target get move-to-end target set ] each
>> target get ;
>>
>> /Jon
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