Brain lock: using array formula within VBA?


E

Ed

I'm just getting my feet wet in using array formulas. I'm beginning to get
a glimpse of their usefulness. Unfortunately, I work almost exclusively
from within VBA, vice entering a formula on the worksheet. I grabbed (I
think!!) how to enter an array formula into the worksheet using VBA. But
somehow it's slipping past me how to use an array formula entirely within
VBA code.

For example, from John Walkenbach's book "Excel 2000 Formulas", he gives an
array formula for determining if a range contains a particular value. In
his example, a single cell is named "TheName", and a 5-column array of names
is named "NameList". His array formula is {=IF(OR(TheName=NameList),
"Found", "Not Found")}.

If I want to do something like this entirely within VBA, then TheName is
likely to be a variable "x" and NameList an array "arr1". And I do not want
to display text in a cell, but do this if true, do that if false. Am I
barking up the wrong tree on this? Or is there just a simple thing I'm
missing?

Ed
 
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B

Bernie Deitrick

Ed,

For example:

Dim x As String
Dim arr1 As Variant
Dim IsThere As Boolean

arr1 = Array("Test1", "Test2", "Test3")

x = "Test2"
IsThere = Not IsError(Application.Match(x, arr1, False))
MsgBox "Match of " & x & " is " & IsThere

x = "Test4"
IsThere = Not IsError(Application.Match(x, arr1, False))
MsgBox "Match of " & x & " is " & IsThere

HTH,
Bernie
MS Excel MVP
 
B

Bob Phillips

Dim x, arr1

x = "TheName"
arr1 = "NameList"
ActiveCell.FormulaArray = "=IF(OR(" & x & "=" & arr1 &
"),""Found"",""Not Found"")"


although you only have a single test so I do not know why there is an OR in
there

--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)
 
E

Ed

What I get from your response, Bernie, is a very useful piece of code (Thank
You!!) and the basic premise that there is no direct translation of an array
formula into VBA code? Instead, you must dissect the array formula and work
out the matching functions and such?

Ed
 
B

Bernie Deitrick

Ed,

The logic is usually different when using VBA. You could write the array formula to a cell and
evaluate it there, capturing the value by reading the cell value, but it is better, IMO, to use the
simplest method depending on where you are, and that is the MATCH solution that I gave. For a 1
dimensional array of names, I'm sure that I would've used the MATCH solution on the worksheet as
well:

=IF(ISERROR(MATCH(TheName,NameList,False)),"Not Found", "Found")

Which wouldn't work if your 5 column array of names was also multirow.

HTH,
Bernie
MS Excel MVP
 
E

Ed

Which wouldn't work if your 5 column array of names was also multirow
Oh, yes - sorry! In the book's example, the array was 10 rows by 5 cols.
You could write the array formula to a cell and
evaluate it there, capturing the value by reading the cell value, but it is better, IMO, to use the
simplest method depending on where you are
I had thought about writing the formula to a cell. But it introduced another
element. If you're processing a large array, writing every value to check
into a cell, recalculating the formula, and reading the answer back into
code could become a real time factor. I knew there was a way to evaluate
basic worksheet formulas in VBA code; I was hoping the same thing could be
done for array formulas.

Ed
 
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B

Bernie Deitrick

Ed,

Actually, if you have the array formula as a string (or as a string that you can build), you can use
the Evaluate method:

MsgBox Evaluate("=IF(OR(TheName=NameList), ""Found"", ""Not Found"")")

HTH,
Bernie
MS Excel MVP
 
E

Ed

Thanks for the reply, Bob.
although you only have a single test so I do not know why there is an OR in
there
Ask John!! <g> Maybe because arr1 is really not only 5 columns, but 10
rows by 5 columns, and I goofed in giving that info?

Actually, what I had more in mind was a way to use the array formula and
it's result entirely within VBA without having to write anything into a
cell.

Ed
 
B

Bernie Deitrick

Ed,

Actually, if you have the array formula as a string (or as a string that you can build), you can use
the Evaluate method:

MsgBox Evaluate("=IF(OR(TheName=NameList), ""Found"", ""Not Found"")")

Still, I would use this for the multi-row multi-column list, since I hate having to build workable
formula strings:

MsgBox IIf(Range("NameList").Find(Range("TheName").Value, _
lookAt:=xlWhole) Is Nothing, "Not Found", "Found")

There's usually about a hundred different ways that you can do the same thing in VBA. It's often a
matter of style...

HTH,
Bernie
MS Excel MVP
 
B

Bob Phillips

Yes I see that now from your discussion with Bernie. At least you have
another tool in the armoury now <G>

Bob
 
E

Ed

Ah, the missing bit! Tom Ogilvy had given me the Evaluate method in an
earlier post, but I didn't understand about putting the entire formula in a
string. This can open up a lot of room to play!

Once again, Bernie, I'm grateful for your help.
Ed
 
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B

Bob Phillips

If you are going to use Evaluate a lot, best to qualify it with the
worksheet that the evaluation is being acted upon, avoids any potential
problems in addressing the activesheet.

--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)
 
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