CFLib.org – Common Function Library Project

Description:
Returns a list of all elements that are both in list LST1 and in list LST2

Return Values:
A list which is the result of ANDing list1 and list2

Example:

<cfset list1 = "10,12,15,20">
<cfset list2 = "12,16,18">
<!---The output will be 12 as 12 is available in both list --->
<cfdump var="#ListAnd(list1,list2)#">

Parameters:

Full UDF Source:

/**
 * Returns a list of all elements that are both in list LST1 and in list LST2
 * v0.9 by Giriraj Kishor Govil
 * v1.0 by Adam Cameron (added support for delimiters and case-sensitivity; used clearer argument & variable names; improved logic slightly)
 * 
 * @param list1      First list to AND (Required)
 * @param list2      Second list to AND (Required)
 * @param delimiter      Delimiter lists use (Optional)
 * @param caseSensitive      Whether AND operation should be case-sensitive (Optional)
 * @return A list which is the result of ANDing list1 and list2 
 * @author Giriraj Kishor Govil (giriraj.govil@gmail.com) 
 * @version 1.0, March 10, 2013 
 */
string function listAnd(required string list1, required string list2, string delimiter=",", boolean caseSensitive=false){
    // exit early if poss
    
    // are the lists the same (given casing requirements)
    if (
        (caseSensitive && !compare(list1,list2))
        ||
        (!caseSensitive && !compareNoCase(list1,list2))
    ){
        return list1;
    }

    // if either is empty, the AND of them will be empty
    if (list1 == "" || list2 == ""){
        return "";    
    }

    list2 = delimiter & list2 & delimiter;    // just makes it easier to do the find operation if all elements are wrapped in delimiters
    if (!caseSensitive){
        list2 = ucase(list2);
    }

    var result = {};
    for (var element in listToArray(list1, delimiter)){
        var item = delimiter & element & delimiter;
        if (!caseSensitive){
            item = ucase(item);
        }
        if (find(item, list2)){
            result[element] = "";
        }
    }
    return structKeyList(result, delimiter);
}