How to get sum of array for specific position? - coldfusion

Question

I have an array:
<cfset fullarray = listtoArray (listofcollumnvalues)>
And it had for example:
fullarray[1]=20
fullarray[2]=11
fullarray[3]=4
fullarray[4]=12.2
etc.
And I wanted to add the sum of the the X position below number:
for example if I wanted the sum of the second element and below
2 + 3 + 4= 27.2

Answer 1

ColdFusion 10 introduced the ArraySlice function. It returns an array when you give it an array, a starting location, and an optional length. So ArraySlice(myArray,3,4) would return a "sub-array" with the elements that start at position 3 and includes 4 elements.
Based on your example:
mySum = ArraySum(ArraySlice(fullarray,2))
If you're on CF 9 or below, you can use a UDF. At CFLib.org there is
arraySlice
arraySlice2
Warning! arraySlice uses "start" and "end" element arguments, while arraySlice2 uses "start" and "length" arguments, like the built-in CF10 function.

Answer 2

Here's something that will work on older versions.
<cfscript>
function listSum(listStr)
{
var delim = ",";
if(ArrayLen(Arguments) GTE 2)
delim = Arguments[2];
return ArraySum(ListToArray(listStr, delim));
}
</cfscript>
Simply envoke it as #listSum(MyListOrArray)#

Answer 3

This is a formatted comment. You define your array as this:
<cfset fullarray = listtoArray (listofcollumnvalues)>
The variable, listofcollumnvalues looks like it might represent results of a query object. If that's the case, You might be doing more work than necessary, because each column of a query is effectively an array. Consider for example this query:
<cfquery name = "queryName">
select field1, numericalField
from etc
</cfquery>
You can actually do stuff like this:
numericalFieldSum = ArraySum(queryName['numericalField'];
It's not exactly what you want, but it illustrates that you might not need your initial command.
Continuing with the assumption that you started with a query, a query of queries might give you what you want.
<cfquery name = "mySum" dbtype = "query">
select sum(numericalField) theSumIWant
from queryName
where your conditions are met
</cfquery>
Of course, if listofcollumnvalues does not come from a query, you should declare this answer to be useless twaddle and downvote accordingly.