CFLib.org – arrayFindSorted

arrayFindSorted(array, value)

Last updated September 30, 2005

author

Kenneth Fricklas
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Version: 1 | Requires: ColdFusion 5 | Library: DataManipulationLib

Rated 2 time(s). Average Rating: 3.0

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")# 
</CFOUTPUT>

Parameters:

Name	Description	Required
array	The array to check.	Yes
value	The value to look for.	Yes

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 (kenf@mallfinder.com) 
 * @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>