Difference between revisions of "LlListFindListNext"

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m (instance is an integer, not a list.)
 
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|p1_type=list|p1_name=src|p1_desc=what to search in (haystack)
|p1_type=list|p1_name=src|p1_desc=what to search in (haystack)
|p2_type=list|p2_name=test|p2_desc=what to search for (needles)
|p2_type=list|p2_name=test|p2_desc=what to search for (needles)
|p3_type=list|p3_name=instance|p3_desc=which instance (needle) to return
|p3_type=integer|p3_name=instance|p3_desc=which instance (needle) to return
|func_footnote=If {{LSLP|test}} is not found in {{LSLP|src}}, -1 is returned.<br/>
|func_footnote=If {{LSLP|test}} is not found in {{LSLP|src}}, -1 is returned.<br/>
The index of the first entry in the list is {{HoverText|0|zero}}<br>
The index of the first entry in the list is {{HoverText|0|zero}}<br>
An expansion of llListFindList which adds an instance parameter to select the nth match to test parameter.
An expansion of llListFindList which adds an instance parameter to select the nth match to test parameter.<br>
llListFindListNext(src, test, 0); is functionally equivalent to llListFindList(src, test);
llListFindListNext(src, test, 0); is functionally equivalent to llListFindList(src, test);<br>
Given a list like [ 'Resident', 'Alexia', 'Resident', 'Bob', 'Resident', 'Steve', 'Resident', 'Evil' ]
Given a list like [ 'Resident', 'Alexia', 'Resident', 'Bob', 'Resident', 'Steve', 'Resident', 'Evil' ]
using a test of [ 'Resident' ] and an instance of 0, 1, 2, 3 would return indices of 0, 2, 4, and 6 respectively.
using a test of [ 'Resident' ] and an instance of 0, 1, 2, 3 would return indices of 0, 2, 4, and 6 respectively.
Selecting the 4th or greater instance will not be found and will return -1.
Selecting the 4th or greater instance will not be found and will return -1.<br>
Reverse indexing is also supported. Using an instance of -1, -2, -3, -4 would respectively return 6, 4, 2, 0
Reverse indexing is also supported. Using an instance of -1, -2, -3, -4 would respectively return 6, 4, 2, 0
And -5 and lower would again return -1
And -5 and lower would again return -1<br>
If {{LSLP|test}} is found at the last index in {{LSLP|src}} the positive index is returned (5th entry of 5 returns 4).
If {{LSLP|test}} is found at the last index in {{LSLP|src}} the positive index is returned (5th entry of 5 returns 4).
|func_desc
|func_desc
Line 65: Line 65:
}</source>
}</source>
|helpers=
|helpers=
An easy way to see if an item exists in a list...
<source lang="lsl2">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 (-)
}</source>
|also_functions=
|also_functions=
{{LSL DefineRow||[[llSubStringIndex]]|Find a string in another string}}
{{LSL DefineRow||[[llSubStringIndex]]|Find a string in another string}}

Latest revision as of 12:11, 9 December 2023

Summary

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

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

• list src – what to search in (haystack)
• list test – what to search for (needles)
• integer instance – which instance (needle) to return

If test is not found in src, -1 is returned.
The index of the first entry in the list is 0
An expansion of llListFindList which adds an instance parameter to select the nth match to test parameter.
llListFindListNext(src, test, 0); is functionally equivalent to llListFindList(src, test);
Given a list like [ 'Resident', 'Alexia', 'Resident', 'Bob', 'Resident', 'Steve', 'Resident', 'Evil' ] using a test of [ 'Resident' ] and an instance of 0, 1, 2, 3 would return indices of 0, 2, 4, and 6 respectively. Selecting the 4th or greater instance will not be found and will return -1.
Reverse indexing is also supported. Using an instance of -1, -2, -3, -4 would respectively return 6, 4, 2, 0 And -5 and lower would again return -1
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

default
{
    touch_end(integer i)
    {
        list myList = [];
        list toFind = [];
        llSay(0, "both lists empty  (expect '0', early abort): " + (string)llListFindListNext(myList, toFind, 0));
        
        myList = [1,2];
        //Consistent with behavior of llListFindList
        llSay(0, "toFind empty (expect immediate match at 0): " + (string)llListFindListNext(myList, toFind, 0));
        llSay(0, "toFind empty (expect immediate match at 1): " + (string)llListFindListNext(myList, toFind, 1));        myList = [];
        toFind = [1,2];
        llSay(0, "myList empty, toFind populated (expect -1): " + (string)llListFindListNext(myList, toFind, 0));
        
        //indices: 0   1   2   3   4   5   6   7   8   9   10   11  12   13
        myList = ["A", 0, "B", 1, "C", 2, "A", 0, "A", 1, "A", "A", 0, <1,2,3>, "c"];
        toFind = ["A", 0];
        llSay(0, "llListFindListNext(myList, toFind, 0) (expect '0'): " + (string)llListFindListNext(myList, toFind, 0));
        llSay(0, "llListFindListNext(myList, toFind, 1) (expect '6'): " + (string)llListFindListNext(myList, toFind, 1));
        llSay(0, "llListFindListNext(myList, toFind, 2) (expect '11'): " + (string)llListFindListNext(myList, toFind, 2));
        llSay(0, "llListFindListNext(myList, toFind, 3) (expect '-1'): " + (string)llListFindListNext(myList, toFind, 3));
        llSay(0, "llListFindListNext(myList, toFind, -1) (expect '11'): " + (string)llListFindListNext(myList, toFind, -1));
        llSay(0, "llListFindListNext(myList, toFind, -2) (expect '6'): " + (string)llListFindListNext(myList, toFind, -2));
        llSay(0, "llListFindListNext(myList, toFind, -3) (expect '0'): " + (string)llListFindListNext(myList, toFind, -3));
        llSay(0, "llListFindListNext(myList, toFind, -4) (expect '-1'): " + (string)llListFindListNext(myList, toFind, -4));        toFind = [3];
        llSay(0, "3 not matched with vector<1,2,3> content (expect '-1'): " + (string)llListFindListNext(myList, toFind, 0));
        toFind = [<1,2,3>];
        llSay(0, "Find a vector:  (expect '13'): " + (string)llListFindListNext(myList, toFind, -1));
        toFind =[<1,2,3>, "c"];
        llSay(0, "Find a vector:  (expect '13'): " + (string)llListFindListNext(myList, toFind, -1));
        toFind =[ "c"];
        llSay(0, "Find last element in reverse  (expect '14'): " + (string)llListFindListNext(myList, toFind, -1));
        llSay(0, "Find last element fwd  (expect '14'): " + (string)llListFindListNext(myList, toFind, 0));
        llSay(0, "Find last element with llListFindList (expect '14'): " + (string)llListFindList(myList, toFind));    }
}

See Also

Functions

•  llSubStringIndex – Find a string in another string

Deep Notes

Signature

function integer llListFindListNext( list src, list test, integer instance );

Haiku

List so full of things.
How do I get the right one?
Make the machine count.

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