LlDeleteSubList

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Revision as of 19:00, 13 July 2008 by Chaz Longstaff (Talk | contribs)

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Summary

Function: list llDeleteSubList( list src, integer start, integer end );

Returns a list that is the src list with the slice from start to end removed.

• list src source
• integer start start index
• integer end end index

start & end support negative indexes. While the function result is different then src, src is not modified, remember to use or store the result of this function.

Specification

Index Positive Negative
First 0 -length
Last length - 1 -1

Indexes

  • Positive indexes count from the beginning, the first item being indexed as 0, the last as (length - 1).
  • Negative indexes count from the far end, the first item being indexed as -length, the last as -1.

Caveats

  • If either start or end are out of bounds the script continues to execute without an error message.
  • start & end will form an exclusion range when start is past end (Approximately: start > end).
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Examples

<lsl>src = llDeleteSubList( src, start, end )</lsl>

<lsl>default {

   state_entry()
   {
       // Create a list of names
       list names = ["Anthony", "Bob", "Charlie", "Dan", "Edgar", "Gerald"];
       
       // Now let's remove values at position 1 through 2.
       names = llDeleteSubList(names, 1, 2);
       // Result:
       // list names = ["Anthony", "Dan", "Edgar", "Gerald"];
       
       // Now let's use an start number higher then our end number
       names = llDeleteSubList(names, 3, 1);
       
       // Result:
       // list names = ["Edgar"];
   }

}</lsl>

The opposite function would be llListInsertList.

Notes

Ranges & Indexes

The easiest way to explain how ranges works is to make all indexes positive. Negative indexes are just a way of counting from the tail end instead of the beginning, all negative indexes have a corresponding equivalent positive index (assuming they are in range). Positive indexes past length (after the last index), or negative indexes past the beginning (before the first index) are valid and the effects are predictable and reliable: the entries are treated as if they were there but were removed just before output.

  • If start <= end then the range operated on starts at start and ends at end. [start, end]
  • Exclusion range: If start > end then the range operated on starts at 0 and goes to end and then starts again at start and goes to -1. [0, end] + [start, -1]
    • If end is a negative index past the beginning, than the operating range would be [start, -1].
    • If end is a positive index past the end, than the operating range would be [0, end].
    • If both start and end are out of bounds than the function would have no operating range (effectively inverting what the function is supposed to do).

See negative indexes for more information.

See Also

Articles

•  Negative Index

Deep Notes

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Signature

function list llDeleteSubList( list src, integer start, integer end );