CFLib.org – Common Function Library Project

Description:
Returns the number of days between a start and end date, excluding a specified list of days, i.e. the number of tuesdays and thursdays - this UDF relies on formula instead of brute force to calculate the days and will perform better than other WeekDays/BusinessDays methods which loop from the start date to end date

Return Values:
Returns a number.

Example:

<cfset BusinessDaysThisMonth = countArbitraryDays(CreateDate(year(now()),month(now()),1),CreateDate(year(now()),month(now()),daysinmonth(now())))>

Parameters:

Full UDF Source:

/**
 * Returns the number of specific days between a start and end date - i.e. weekdays or workdays.
 * 
 * @param startdate      Starting date. (Required)
 * @param enddate      Ending date. (Required)
 * @param exclude      Days of the week (as a number) to include. Defaults to 1,7 (Optional)
 * @param includeStartDate      Boolean value to indicate if startdate is included in count. Defaults to true. (Optional)
 * @return Returns a number. 
 * @author Isaac Dealey (info@turnkey.to) 
 * @version 1, December 5, 2006 
 */
function countArbitraryDays(startdate,enddate) { 
    var exclude = "1,7"; var IncludeStartDate = true; 
    var daysperweek = 0; var days = 0; 
    var weekday = ArrayNew(1); var x = 0; 
    var maxdays = DateDiff("d",dateadd("d",-1,startdate),enddate); 
    
    switch (arrayLen(arguments)) { 
        case 4: { IncludeStartDate = arguments[4]; } 
        case 3: { exclude = arguments[3]; } 
    } 
    
    // create an array to hold days of the week with 1 or 0 indicating if the day is counted 
    arraySet(weekday,1,7,1); exclude = listToArray(exclude); 
    for (x = 1; x lte arrayLen(exclude); x = x + 1) { weekday[exclude[x]] = 0; } // set the value of any excluded day to 0 
    daysperweek = arraySum(weekday); // count the number of included days in a full week 
    days = daysperweek * int(maxdays/7); // get the number of included days in all full weeks 
    for (x = 1; x lte maxdays mod 7; x = x + 1) { // add any remaining days in the last partial week 
        days = days + weekday[dayofweek(enddate)]; 
        enddate = dateadd("d",-1,enddate); 
    } 
    
    // if excluding the start date, remove the value that might have been added for the starting day 
    if (not includeStartDate) { days = days - weekday[dayofweek(startdate)]; } 
    
    return days; 
}