Difference between revisions of "LlListFindList"

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(-1 returned from llListFindList is not a generic error (of which nothing is known). It has a specific meaning of NOT FOUND)
 
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{{LSL_Function
{{LSL_Function
|inject-2={{Issues/SVC-5146}}
|inject-2={{Issues/SVC-5146}}{{Issues/BUG-10924}}
|func=llListFindList
|func=llListFindList
|func_id=201|func_sleep=0.0|func_energy=10.0
|func_id=201|func_sleep=0.0|func_energy=10.0
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* If {{LSLP|test}} is an {{HoverText|empty list|[]}} the value returned is {{HoverText|0|zero}} rather than -1.
* If {{LSLP|test}} is an {{HoverText|empty list|[]}} the value returned is {{HoverText|0|zero}} rather than -1.
|constants
|constants
|examples=<lsl>list numbers = [1, 2, 3, 4, 5];
|examples=<source lang="lsl2">list numbers = [1, 2, 3, 4, 5];
default
default
{
{
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         }
         }
     }
     }
}</lsl>
}</source>
<lsl>//You can also search for two items at once to find a pattern in a list
<source lang="lsl2">//You can also search for two items at once to find a pattern in a list
list avatarsWhoFoundMagicLeaves = ["Fire Centaur","Red Leaf"];
list avatarsWhoFoundMagicLeaves = ["Fire Centaur","Red Leaf"];
default
default
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         }
         }
     }
     }
}</lsl>
}</source>
|helpers=
|helpers=
An easy way to see if an item exists in a list...
An easy way to see if an item exists in a list...
<lsl>if(~llListFindList(myList, (list)item))
<source lang="lsl2">if(~llListFindList(myList, (list)item))
{//it exists
{//it exists
     //This works because ~(-1) == 0
     // This works because ~(-1) produces 0, but ~ of any other value produces non-zero and causes the 'if' to succeed
     //It saves bytecode and is faster then doing != -1
    // So any return value (including 0) that corresponds to a found item, will make the condition succeed
     //This is a bitwise NOT (~) not a negation (-)
     // It saves bytecode and is faster then doing != -1
}</lsl>
     // This is a bitwise NOT (~) not a negation (-)
}</source>
|also_functions=
|also_functions=
{{LSL DefineRow||[[llSubStringIndex]]|Find a string in another string}}
{{LSL DefineRow||[[llSubStringIndex]]|Find a string in another string}}
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|sort=ListFindList
|sort=ListFindList
|cat1=List
|cat1=List
|haiku={{Haiku|Where are my car keys?|Has anyone seen my keys?|Oh! In my pocket.}}
|cat2
|cat2
|cat3
|cat3
|cat4
|cat4
}}
}}

Latest revision as of 04:04, 16 December 2015

Summary

Function: integer llListFindList( list src, list test );
0.0 Forced Delay
10.0 Energy

Returns the integer index of the first instance of test in src.

• list src what to search in (haystack)
• list test what to search for (needle)

If test is not found in src, -1 is returned.
The index of the first entry in the list is 0
If test is found at the last index in src the positive index is returned (5th entry of 5 returns 4).

Caveats

  • Strict type matching and case sensitivity is enforced.
    • "1" != 1
    • "1.0" != 1.0
    • 1 != 1.0
    • "a822ff2b-ff02-461d-b45d-dcd10a2de0c2" != (key)"a822ff2b-ff02-461d-b45d-dcd10a2de0c2"
    • "Justice" != "justice"
  • If test is an empty list the value returned is 0 rather than -1.

Examples

list numbers = [1, 2, 3, 4, 5];
default
{
    state_entry()
    {
        integer index = llListFindList(numbers, [3]);
        if (index != -1)
        {
            list three_four = llList2List(numbers, index, index + 1);
            llOwnerSay(llDumpList2String(three_four, ","));
            // Object: 3,4
        }
    }
}
//You can also search for two items at once to find a pattern in a list
list avatarsWhoFoundMagicLeaves = ["Fire Centaur","Red Leaf"];
default
{
    state_entry()
    {
        integer index = llListFindList(avatarsWhoFoundMagicLeaves, ["Fire Centaur","Red Leaf"]);
        if (index != -1)
        {
            list output = llList2List(avatarsWhoFoundMagicLeaves, index, index + 1);
            llOwnerSay(llDumpList2String(output, ","));
            // Object: Fire Centaur, Red Leaf
        }
    }
}

Useful Snippets

An easy way to see if an item exists in a list...

if(~llListFindList(myList, (list)item))
{//it exists
    // This works because ~(-1) produces 0, but ~ of any other value produces non-zero and causes the 'if' to succeed
    // So any return value (including 0) that corresponds to a found item, will make the condition succeed
    // It saves bytecode and is faster then doing != -1
    // This is a bitwise NOT (~) not a negation (-)
}

See Also

Functions

•  llSubStringIndex Find a string in another string

Deep Notes

Signature

function integer llListFindList( list src, list test );

Haiku

Where are my car keys?
Has anyone seen my keys?
Oh! In my pocket.