CFLib.org – Common Function Library Project

quartile(values, quartile)

Last updated June 11, 2009

author

Nathan Mische

Version: 0 | Requires: CF5 | Library: MathLib

Description:
Returns the first, second, or third quartile value for a set of numeric values.

Return Values:
Returns a number.

Example:

<cfset values=[7,15,36,39,40,41] />
<cfset q = Quartile(values,3) />

Parameters:

Name Description Required
values Values to parse. Yes
quartile Numeric value between 1 and 3. Yes

Full UDF Source:

/**
 * Returns the first, second, or third quartile value for a set of numeric values.
 * 
 * @param values 	 Values to parse. (Required)
 * @param quartile 	 Numeric value between 1 and 3. (Required)
 * @return Returns a number. 
 * @author Nathan Mische (nmische@gmail.com) 
 * @version 0, June 11, 2009 
 */
function quartile(values, q) {
	var valueArray = 0;
	var numValues = 0;
	var leftIndex = 0;
	var rightIndex = 0;
	var middleIndex = 0;
	var median = 0;
	var i = 0;
	var halfValues = ArrayNew(1);
	var val = 0;

	if (IsArray(values)){
		valueArray = Duplicate(values);
	} else {
		valueArray = ListToArray(values);
	}

	ArraySort(valueArray,"numeric");
	numValues = ArrayLen(valueArray);

	// get the median
	if((numValues mod 2) eq 0) {
		leftIndex = Int(numValues/2);
		rightIndex = Int(numValues/2) + 1;
		median = (valueArray[leftIndex] + valueArray[rightIndex]) / 2;
	} else {
		middleIndex = Int(numValues/2) + 1;
		median = valueArray[middleIndex];
	}

	// return the quartile
	if (q eq 1) {
		for (i = 1; i lte numValues; i = i + 1){
			val = valueArray[i];
			if ( val lt median) {
				ArrayAppend(halfValues,val);
			} else {
				break;
			}
		}
		return Quartile(halfValues,2);
	} else if (q eq 2) {
		return median;
	} else if (q eq 3) {
		for (i = numValues; i gt 0; i = i - 1){
			val = valueArray[i];
			if ( val gt median) {
				ArrayAppend(halfValues,val);
			} else {
				break;
			}
		}
		return Quartile(halfValues,2);
	}

	// return a blank string if invalid quartile
	return "";

}
blog comments powered by Disqus

Search CFLib.org


Latest Additions

Kevin Cotton added
date2ExcelDate
May 5, 2016

Raymond Camden added
CapFirst
April 25, 2016

Chris Wigginton added
loremIpsum
January 18, 2016

Gary Stanton added
calculateArrival...
November 19, 2015

Sebastiaan Naafs - van Dijk added
getDaysInQuarter
November 13, 2015

Created by Raymond Camden / Design by Justin Johnson