llListSort

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Revision as of 15:56, 22 October 2007 by Ppaatt Lynagh (talk | contribs) (spelling: to affected from effected, to descending from desending, to ascending from assending, also mention slowness of bubble sort more prominently)
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Summary

Function: list llListSort( list src, integer stride, integer ascending );

Returns a list that is src sorted by stride.

• list src List to be sorted.
• integer stride number of entries per stride, if less then 1 it is assumed to be 1.
• integer ascending if FALSE then the sort order is descending, otherwise the order is ascending.

Specification

A slow bubble sort is employed to perform the sort.
The sort order is affected by type.
Each type is sorted individually and then feathered to have the same order of types.

llListSort([1, "C", 3, "A", 2, "B"], 1, TRUE) == [1, "A", 2, "B", 3, "C"]
llListSort([1, 3, 2, "C", "A", "B"], 1, TRUE) == [1, 2, 3, "A", "B", "C"]

llListSort([1, "C", 3, "A", 2, "B"], 2, TRUE) == [1, "C", 2, "B", 3, "A"]

Caveats

A bubble sort is a sorting algorithm with a Big O of N*N. Why Linden Labs did not use a N*log(N) sorting algorithm such as Heap Sort or Merge Sort is unkown...

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Examples

list numbers = [3, "three", 2, "two", 1, "one"];
default
{
    state_entry()
    {
        llOwnerSay(llDumpList2String(numbers, ","));
        // Object: 3,three,2,two,1,one
        numbers = llListSort(numbers, 2, TRUE);
        llOwnerSay(llDumpList2String(numbers, ","));
        // Object: 1,one,2,two,3,three
    }
}

Deep Notes

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Source

lsa_bubble_sort(): 'linden\indra\lscript\lscript_alloc.h'

Signature

function list llListSort( list src, integer stride, integer ascending );