ListAddUnique ( InList ; InValue )

Add given value, InValue, to given list, InList, but only if not already in list.

Average rating: 4.6 (15 votes) Log in to vote

Richard DeShong - Show more from this author
Logic Tools
http://logictools.com

Sample input:

ListAdd ( "A¶B" ; "B" )

Sample output:

"A¶B"

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

Case(
   IsEmpty ( InList )  or  InList = "Empty" ; InValue ;
   IsEmpty ( InValue )  or  InValue = "Empty" ; InList ;
   IsEmpty ( FilterValues ( InList ; InValue ) ) ; InList & "¶" & InValue ;
   InList
)
/*
   Make sure InValue is in list, but only once.
   Logic:
   If either parameter is <empty>, return the other;
   Else If InValue is not in InList, add it
   Else return InList
*/

My typical use of this function: I scroll through a found set of records and collect a list of unique values from a given field.

This is part of a series of LIST functions.
ListAdd, ListAddUnique, ListExist, ListGet, ListToggle.
Each uses the same name format: ListDoSomething
Each uses the same parameter format: InList ; InValue.

They also work in concert with two SET functions:
SetVar( InText ) and SetField( InText )
These are all designed to work with variables and to keep the variables from being
un-set (removed from memory), by using the string "Empty" to indicate IsEmpty().
Example:
If a field, MyField, is empty and I use MyVar = SetVar( MyField ) then MyVar = "Empty".

~~~

Comments

		Eric, SJSU Mar 15, 2017
This is awesome! would you consider being able feed a list of values to add if any one is unique? in other words. make sure this list of values contains this other list of values

		Richard DeShong, Logic Tools Mar 15, 2017
Hi Eric, what you are asking sounds like a list merge. For a non-recursive version of merging two lists, check out Michael Rhodes' MergeLists(_array1;_array2).

Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

ListAddUnique ( InList ; InValue )

Comments

Support this website.

Support this website.