LlSubStringIndex: Difference between revisions

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confirm our Efficiency Tester claims of equal run time with the much different Code Racer benchmark
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Note: The llSubStringIndex function returns -1 only when not found and the ~ operator returns zero only for -1, so the arcane combination ~llSubStringIndex returns zero only for not found, else nonzero for found.
Note: The llSubStringIndex function returns -1 only when not found and the ~ operator returns zero only for -1, so the arcane combination ~llSubStringIndex returns zero only for not found, else nonzero for found.


Note: Smaller was not noticeably faster when our [[Efficiency Tester]] measured the expression <nowiki>{ contains("wiki.secondlife.com", "wiki"); }</nowiki>.
Note: Smaller was not noticeably faster when our [[Code Racer]] and [[Efficiency Tester]] harnesses measured the expression <nowiki>{ contains("wiki.secondlife.com", "wiki"); }</nowiki>.


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Revision as of 16:58, 16 October 2007

Summary

Function: integer llSubStringIndex( string source, string pattern );
0.0 Forced Delay
10.0 Energy

Returns an integer that is the index of pattern in source.

• string source
• string pattern

If pattern is not found in source, -1 is returned.
The index of the first character in the string is 0

Caveats

  • Performs a literal match (case sensitive).
    • Wildcards and RegEx are not supported.
  • Attempting to match an empty string ("") will return 0 instead of -1.

Examples

Matching against last names:

default
{
    state_entry()
    {
        llSensorRepeat("", NULL_KEY, AGENT, PI, 96.0, 20);
    }
    
    sensor(integer NumDet)
    {
        integer i;
        
        //Loop through all the sensor data and match against " Linden", 
        //this causes it to match with any last name of Linden (since there can't be spaces before the firstname)
        //Alternatively you could match a firstname with "FirstName "
        for(i = 0; i < NumDet; ++i)
            if(~llSubStringIndex(llDetectedName(i), " Linden"))
                llInstantMessage(llDetectedKey(i), "Hello, I see you!");
    }
}

Useful Snippets

Easy ways to see if a string exists in another string...

1. Correct at a glance and drearily conventional:

integer contains(string haystack, string needle) // http://wiki.secondlife.com/wiki/llSubStringIndex
{
    return 0 <= llSubStringIndex(haystack, needle);
}

2. Smaller (~54 bytes rather than ~60):

integer contains(string haystack, string needle) // http://wiki.secondlife.com/wiki/llSubStringIndex
{
    return ~llSubStringIndex(haystack, needle);
}

Note: The llSubStringIndex function returns -1 only when not found and the ~ operator returns zero only for -1, so the arcane combination ~llSubStringIndex returns zero only for not found, else nonzero for found.

Note: Smaller was not noticeably faster when our Code Racer and Efficiency Tester harnesses measured the expression { contains("wiki.secondlife.com", "wiki"); }.

integer startswith(string haystack, string needle)
{
	return (0 == llSubStringIndex(haystack,needle));
}

NOTE: This function doesn't use llSubStringIndex

integer endswith(string haystack, string needle)
{
	return (llGetSubString(haystack,llStringLength(haystack)-llStringLength(needle),-1) == needle);
}

See Also

Functions

•  llListFindList Find a list in another list

Deep Notes

Signature

function integer llSubStringIndex( string source, string pattern );