Category talk:LSL List

I want to document the fact that the following two expressions are NOT the same somehow.

[1] list_var += [(string)key_var]; [2] list_var += (string)key_var;

Why does this matter? why consider the following line of code:

index = llListFindList(list_var, [(string)key_var] );

If method [1] is used before the line above,you will find your value, however if you use method [2], you will not.

After much frustration I wanted to share this in hope someone else will not fall into the pit, or if it is a bug, it can be put in Jira. I'll let one of the Wiki gods decide what to do with this. --Awsoonn Rawley

I'll look into it, this sounds like a bug. Those two expressions should be equivalent. -- Strife Onizuka 18:26, 3 June 2007 (PDT)

I've done some testing and I cannot replicate your problem. Are you aware that indexing starts at zero and not one? -- Strife Onizuka 15:56, 5 June 2007 (PDT)

try this --Awsoonn Rawley 04:35, 6 June 2007 (PDT)

default
{
    state_entry()
    {
        list lst;
        key  uuid = llGetKey();
        
        lst = ["bob", "tom", "jerry"];
        
        lst += (string)uuid;
        
        llSay(0, (string)llListFindList(lst, [(string)uuid]) );
    }
}

---

I would really just like some documentation on this page about how to index into a list at all. Thanks - Kendown Baroque 00:48, 28 August 2007 (PDT)

On Concatenation

I have read in many places that there are two ways to concatenate lists, the "standard" way and a memory-saving "voodoo" technique. The standard way looks like this:

Code: "Standard" List Concatenation

list myList = ["element1"]; myList += ["element2"];

The "voodoo" technique looks like this:

Code: "Voodoo" List Concatenation

list myList = ["element1"]; myList = (myList=[]) + mylist + ["element2"];

So, being a bit of a computer scientist, I decided to give it a test. Here's my test code:

Code: Test Code - List Concat Standard

integer REPS = 30; list myList; integer i; default { // INIT state_entry() { llOwnerSay("Testing memory usage..."); myList = []; for (i = 0; i < REPS; ++i) { myList += ["test3.0", "test3.1", "test3.2", "test3.3", "test3.4", "test3.5", "test3.6", "test3.7", "test3.8", "test3.9"]; } llOwnerSay("List Standard Short Format Post-Concat 10*" + (string) REPS + " compound: " + (string) llGetFreeMemory()); myList = []; for (i = 0; i < REPS; ++i) { myList = ["test3.0", "test3.1", "test3.2", "test3.3", "test3.4", "test3.5", "test3.6", "test3.7", "test3.8", "test3.9"] + myList; } llOwnerSay("List Standard Long Format Pre-Concat 10*" + (string) REPS + " compound: " + (string) llGetFreeMemory()); } }

Output:

• Testing memory usage...
• List Standard Short Format Post-Concat 10*30 compound: 4261
• List Standard Long Format Pre-Concat 10*30 compound: 4261

Code: Test Code - List Concat Voodoo

integer REPS = 30; list myList; integer i; default { // INIT state_entry() { llOwnerSay("Testing memory usage..."); myList = []; for (i = 0; i < REPS; ++i) { myList = (myList=[]) + myList + ["test4.0", "test4.1", "test4.2", "test4.3", "test4.4", "test4.5", "test4.6", "test4.7", "test4.8", "test4.9"]; } llOwnerSay("List Voodoo Post-Concat 10*" + (string) REPS + " compound: " + (string) llGetFreeMemory()); myList = []; for (i = 0; i < REPS; ++i) { myList = (myList=[]) + ["test4.0", "test4.1", "test4.2", "test4.3", "test4.4", "test4.5", "test4.6", "test4.7", "test4.8", "test4.9"] + myList; } llOwnerSay("List Voodoo Pre-Concat 10*" + (string) REPS + " compound: " + (string) llGetFreeMemory()); } }

Output:

• Testing memory usage...
• List Voodoo Post-Concat 10*30 compound: 9795
• List Voodoo Pre-Concat 10*30 compound: 9739

Results

Interesting results... A gain of 5534 to 5478 bytes of memory for these tests.

Remember, bigger numbers mean more free memory, therefore less memory being used.

Cron Stardust 00:14, 31 December 2007 (PST)