CFLib.org – Common Function Library Project

Description:
Locate a value in an already-sorted array. Case-insensitive for strings. Code is useful since converting to a list would require finding a unique delimiter.

Return Values:
Returns the position of the match, or 0.

Example:

<CFSET a1 = ListToArray("1,2,4,5,10,12")>
<CFOUTPUT>
#arrayFindSorted(a1, "10")# <!--- displays 5 --->
</CFOUTPUT>

Parameters:

Full UDF Source:

<cfscript>
/**
 * Locate a value in an already-sorted array.
 * 
 * @param array 	 The array to check. (Required)
 * @param value 	 The value to look for. (Required)
 * @return Returns the position of the match, or 0. 
 * @author Kenneth Fricklas (&#107;&#101;&#110;&#102;&#64;&#109;&#97;&#108;&#108;&#102;&#105;&#110;&#100;&#101;&#114;&#46;&#99;&#111;&#109;) 
 * @version 1, September 30, 2005 
 */
function arrayFindSorted(arrayX, value) 
{
	var m = 0;	
	var found = 0;
	var done = 0;
	var hi = arrayLen(arrayX)+1;
	var lo = 1;
	var i = 1;
	var maxtest = 500;
	do {
		m = (hi + lo) \ 2;
		if (arrayX[m] EQ value)
		{
			found = 1;
			done = 1;
		}
		else
		{
			if ((m EQ lo) or (m EQ hi))
				done = 1; /* not found */
			else
			{	
				if (value LT arrayX[m])
				{
				/* higher */
					hi = m;
				}
				else
				{
				/* lower */
					lo = m;
				}
			}
		}
		if (i EQ maxtest)
			{
			done = 1;
			writeoutput("Error! overflow in search");
			}
		else
			i = i + 1;
	} while (done EQ 0);
	if (found)
		return m;
	else
		return 0;
}
</cfscript>