CFLib.org – Common Function Library Project

Description:
Removes items from the first list that are in the second list and returns the edited list. Lists one and two are required, and optionally, pass in a delimiter and option to remove all instances of items in list 2, or to remove the first one. (default is remove 1)

Return Values:
Returns a string.

Example:

<cfoutput>
ListRemoveList("3,4,dog,g,b,d,t,e,22,22,22,33,44,77,$,dog", "$,dog,22", ",","all") =
#ListRemoveList("3,4,dog,g,b,d,t,e,22,22,22,33,44,77,$,dog", "$,dog,22", ",","all")#
<br><br>

ListRemoveList("3,4,dog,g,b,d,t,e,22,22,22,33,44,77,$,dog", "$,dog,22", ",", "one") = 
#ListRemoveList("3,4,dog,g,b,d,t,e,22,22,22,33,44,77,$,dog", "$,dog,22", ",", "one")#
</cfoutput>

Parameters:

Full UDF Source:

/**
 * Removes second list from first list, accepting an optional delimiter and whether to remove one or all list items.
 * 
 * @param list1      List to parse. (Required)
 * @param list2      List of items to remove. (Required)
 * @param delimiters      Delimiter. Defaults to a comma. (Optional)
 * @param scope      One or all. If one, removes one instance of the item from list2. All if otherwise. Defaults to one. (Optional)
 * @return Returns a string. 
 * @author Ann Terrell (ann@landuseoregon.com) 
 * @version 2, May 10, 2005 
 */
function ListRemoveList(list1,list2)    {
  var delimiters    = ",";
  var removeall = false;
  var listReturn = list1;
  var position = 1;

  // default list delimiter to a comma unless otherwise specified
  if (arrayLen(arguments) gte 3) delimiters=arguments[3];

  // default removal pattern is remove one of each item in list2
  if (arrayLen(arguments) eq 4 and  arguments[4] eq "all") removeall=true;
  
  //checking list1
  for(position = 1; position LTE ListLen(list2,delimiters); position = position + 1) {
    value = ListGetAt(list2, position , delimiters );
     
    if (removeall) {
           while (ListFindNoCase(listReturn, value , delimiters ) NEQ 0)
              listReturn = ListDeleteAt(listReturn, ListFindNoCase(listReturn, value , delimiters ) , delimiters );
        }
    else {
            if (ListFindNoCase(listReturn, value , delimiters ) NEQ 0)
              listReturn = ListDeleteAt(listReturn, ListFindNoCase(listReturn, value , delimiters ) , delimiters );
        }
    }
        
  return listReturn;
}