Topic: List - Comparison & Filter

[Matthew H]

I was wondering if anyone could help me figure out how to filter out a list.
If the below does not make since, let me know and I will try to re-word it.

I have two data lists.
ListA '("Item6-2" "Item6" "Item4" "Item8" "Item7" "Item4-12")
ListB '("Item7" "Item3" "Item4-12" "Item9" "Item4" "Item1" "Item5")

I would like to create three separate lists with the following conditions
ListC is ListA, but items that are also in ListB are excluded.
ListC '("Item6-2" "Item6" "Item8")

ListD is ListA, but only items that are also in ListB are included.
ListD '("Item4" "Item7" "Item4-12")

ListE is ListB, but with items in ListA excluded.
ListE '("Item3" "Item9" "Item1" "Item5")

Thanks in advance,
Matthew H.

[Lee Mac]

You can use my library of List Set functions for this:

• List Difference
• List Union
• List Intersection
• List Symmetric Difference

Code: [Select]

_$ (setq ListC (LM:listdifference ListA ListB))
("Item6-2" "Item6" "Item8")

Code: [Select]

_$ (setq ListD (LM:listintersection ListA ListB))
("Item4" "Item7" "Item4-12")

Code: [Select]

_$ (setq ListE (LM:listdifference ListB ListA))
("Item3" "Item9" "Item1" "Item5")

[Matthew H]

You can use my library of List Set functions for this:

• List Difference
• List Union
• List Intersection
• List Symmetric Difference

Code: [Select]

_$ (setq ListC (LM:listdifference ListA ListB))
("Item6-2" "Item6" "Item8")

Code: [Select]

_$ (setq ListD (LM:listintersection ListA ListB))
("Item4" "Item7" "Item4-12")

Code: [Select]

_$ (setq ListE (LM:listdifference ListB ListA))
("Item3" "Item9" "Item1" "Item5")

Lee,

That is a wonderful function library!
I was able to get what I need and more, much appreciated!!

Thanks,
Matthew H.

[Lee Mac]

You're most welcome Matthew - I'm glad you found it useful

[BIGAL]

If you look in the Challenges section of this forum subject there are many solutions to list problems worth a quick look sometimes to see if matches problem.

Not withstanding Lee's great contribution.