0 votes
in VBA by Beginner (5 points)

I have 2 lists that I need to compare. List 1 may contain, for example: apples, oranges, plums, pears. List 2 may contain: apples, apples, oranges, plums, plums, pears. If list 1 should have the duplicate values (there should be 2 instances of apples and plums, not just 1), would the macro show list 1 as missing 1 instance of apples and 1 instance of plums?

Source: VBA Compare two lists and show missing values

1 Answer

+2 votes
by Skilled (419 points)
selected by
 
Best answer


Hi trrider53,

Great question! Before we get to the answer, we need to fix a minor typo in the posted code that you referenced:

' change the first occurrence of LastRow_1 to LastRow_2


.Value = Evaluate("IF(COUNTIF(" & Col_2 & StartRow & ":" & Col_2 & LastRow_2 & ", " & Col_1 & StartRow & ":" & Col_1 & LastRow_1 & "),""""," & Col_1 & StartRow & ":" & Col_1 & LastRow_1 & ")")

' This fix will allow list 2 to be longer than list one.

Now, no matter which list has the duplicates, the macro will not output the instances. COUNTIF can't tell one apple from another. More accurately, the macro is designed to detect TRUE or FALSE, even though it's obscurred by the output.

IF(logical test,OUTPUT if TRUE, OUTPUT if FALSE)

The logical test really evaluates to  either a non-zero value, which is TRUE, or a value of zero, which is FALSE. That's why the COUNTIF function can detect missing fruit: it evaluates to zero for any fruit that is in List 1, but not List 2.

By the way, this means that you need a second test. That gets complex, really fast. Instead, you may want to look at the dictionary object. See the reference, below. On that page, you'll learn how to list unique items. This should point you in the right direction.

Cheers,

Mitch

Reference:

Excel VBA Dictionary Keys and Items

 

by Super Expert (3.2k points)
Thanks for pointing out that typo, Mitch! I'll get it fixed with the next publication!
by Skilled (419 points)
You're welcome, Ryan. I had a lot of fun with that macro!

Cheers,

Mitch

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