# User:Dora Gustafson/occurences

## Count Occurrences in a list

Look for and count anything, that can be an element, in a list

This script is an example which include a list: "haystack" and an element: "needle"
Here "haystack" and "needle" are constants and only meant to make up a working script
```// count occurrences in list; by Dora Gustafson, Studio Dora 2014
// v1.1 inline code

default
{
state_entry()
{
list haystack = [1,2,1,2,1,2,3,2,4,5,2,6,4,2,3,2,1,8];
list needle = [2];
integer i = 0;
integer j = 0;
integer k = llListFindList( haystack, needle);
integer m = llGetListLength( haystack );
while ( k >= 0 && i < m )
{
i += k+1;
k = llListFindList( llList2List( haystack, i, -1), needle);
++j;
}
llOwnerSay((string)needle+" occurs "+(string)j+" times in "+llDumpList2String( haystack, ", "));
}
}```

This program is straight, a recursive approach follows

```// count occurrences in list; by Dora Gustafson, Studio Dora 2014
// v1.1 inline code
// v1.2 recursive approach

list haystack = [1,2,1,2,1,2,3,2,4,5,2,6,4,2,3,2,1,8];
list needle = [2];
integer j = 0;

tin( list L )
{
integer k = llListFindList( L, needle);
if ( k >= 0 )
{
++j;
if ( k+1 < llGetListLength(L) ) tin( llList2List( L, k+1, -1));
}
}

default
{
state_entry()
{
tin( haystack);
llOwnerSay((string)needle+" occurs "+(string)j+" times in "+llDumpList2String( haystack, ", "));
}
}```

The advantage of recursion over straight code is a shorter code(the code is reused)
The disadvantages are longer execution time and more overhead generated at runtime

For these reasons the recursion approach is a bad choice to search a long list in LSL