CFLib.org – Common Function Library Project

Description:
This function compares two lists and will return a new list containing the difference between the two input lists. This function is different from ListDiff as it treats duplicate elements within the lists as distinct elements.

Return Values:
Returns a string.

Example:

<cfoutput>#ListDiffDup("1,2,3","1,2,3,3,3,4")#</cfoutput>

Parameters:

Full UDF Source:

/**
 * Compares two lists and returns the elements that are unique for each list.
 * Added var statements.
 * 
 * @param list1      The first list. (Required)
 * @param list2      The second list. (Required)
 * @param delimiters      Delimiter for both lists. Defaults to a comma. (Optional)
 * @return Returns a string. 
 * @author Anonymous (anonymous@gmail.com) 
 * @version 1, October 4, 2007 
 */
function ListDiffDup(list1,list2)    {
  var delimiters    = ",";
  var listReturn = "";
  
  // Use two temporary lists.
  var temp1 = list1;
  var temp2 = list2;
  
  var i = 1;
  var pos = 1;

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


    // Loop over the first list, eliminate all duplicate elements from the temp2 list.
  for (i=1; i lte ListLen(list1,delimiters); i=i+1) {
      pos = ListFindNoCase(temp2,ListGetAt(list1,i,delimiters),delimiters);
    if (pos neq 0) {
        temp2 = ListDeleteAt(temp2,pos,delimiters);
    }
  }

    // Loop over the second list, eliminate all duplicate elements from the temp1 list.
  for (i=1; i lte ListLen(list2,delimiters); i=i+1) {
      pos = ListFindNoCase(temp1,ListGetAt(list2,i,delimiters),delimiters);
    if (pos neq 0) {
        temp1 = ListDeleteAt(temp1,pos,delimiters);
    }
  }

  // Append all distinct elements from the first list to the return list
  for (i=1; i lte ListLen(temp1,delimiters); i=i+1) {
      listReturn = ListAppend(listReturn,ListGetAt(temp1,i,delimiters),delimiters);
  }
        
  // Append all distinct elements from the second list to the return list.
  for (i=1; i lte ListLen(temp2,delimiters); i=i+1) {
      listReturn = ListAppend(listReturn,ListGetAt(temp2,i,delimiters),delimiters);
  }

  return listReturn;
}