I have a QBasic function that takes two arrays as parameters. I'd like to know if it's possible to find the number of dimensions those arrays have in the function.
For context, I'm writing an assertArrayEqual function for a QBasic unit testing library.
There is no way to accomplish this. As stated, you can determine the lower and upper bounds, but you must know beforehand how many dimensions the array contains. To my knowledge this is not even available in higher level versions.
It can be done but it is not pretty: (QB64 source).
REM sample code to find number of dimensions in an array
DIM a(2, 2, 2) AS INTEGER
DIM SHARED E AS INTEGER
ON ERROR GOTO 10
CALL array(a())
END
10 E = -1: RESUME NEXT
SUB array (a() AS INTEGER)
DO
X = X + 1
T = UBOUND(a, X)
IF E THEN
X = X - 1
PRINT "Array has"; X; "dimensions."
EXIT DO
END IF
LOOP
END SUB
Related
I am trying to make a simple simulation in Excel VBA in which we roll two dices. What is the probability of getting "1"+"2" or "1"+"3"?
This is my code:
Sub ProbabilityMeyerArray()
Dim i As Long
Dim ArrayDices(1 To 100000, 1 To 2) As Variant
Dim ArrayResult(1 To 100000) As Variant
'Simulation
For i = 1 To 100000
ArrayDices(i, 1) = WorksheetFunction.RandBetween(1, 6)
ArrayDices(i, 2) = WorksheetFunction.RandBetween(1, 6)
If (ArrayDices(i, 1) = 1 And ArrayDices(i, 2) = 3) _
Or (ArrayDices(i, 1) = 1 And ArrayDices(i, 2) = 2) _
Or (ArrayDices(i, 1) = 3 And ArrayDices(i, 2) = 1) _
Or (ArrayDices(i, 1) = 2 And ArrayDices(i, 2) = 1) Then
ArrayResult(i) = 1
Else
ArrayResult(i) = 0
End If
Next i
'print the values to cells
Range("A1:B100000").Value = ArrayDices
Range("C1:C100000").Value = WorksheetFunction.Transpose(ArrayResult)
'Calculate the probability
Probability = Application.WorksheetFunction.Sum(ArrayResult) / 100000
MsgBox "The Probability is " & Probability
End Sub
The problem is that when I print the values from arrays to the cells, then in column C I have 0 and 1 (as it should be), but then from row 34465 I get NA. Here is a screenshot:
https://ibb.co/7jsjjJC
So, for some reason it starts putting NA instead of 0 and 1. The calculation does not work properly either, because the probability is too low, and I guess this is because it only counts the first 34464 zeros and ones, while dividing with 100 000. Can you help me understand what is wrong here? It seems to be a problem with (my understanding of) arrays, since I can run a similar simulation without arrays (by simply using cells), and it works.
Thanks in advance!
As #RaymondWu said in the comments, the problem is that the Transpose function has a limit to the length of the array it can manipulate. This limit is somewhere between 65k and 66k columns.
Indeed, your code will run as expected for 65k iterations.
You can easily avoid using transpose and to be honest I don't see the reason to use it in the first place.
Instead of declaring your array as Dim ArrayResult(1 To 100000) As Variant which by default makes it 1 row x 100000 columns, you can declare it as so:
Dim ArrayResult(1 To 100000, 1 To 1) As Variant
This will make it 100000 rows x 1 columns, which can now be written in a column in excel easily like so:
Range("C1:C100000").Value = ArrayResult
Of course you will also need to change the code accordingly where needed:
ArrayResult(i,1) = 1
Else
ArrayResult(i,1) = 0
A few other tips:
Always use Option Explicit at the very top of the code. It makes the declaration of variables mandatory and it helps to avoid mistakes
Always use explicit references. When referencing Ranges the best practice is to define the worksheet to which they belong e.g. ThisWorkbook.Worksheets("Sheet1").Range("C1:C100000").Value = ArrayResult
(Fair Warning, I am self taught on VBA so I apologize in advance for any cringe-worthy coding or notations.)
I have an estimating worksheet in excel. The worksheet will have a section for the user to input variables (which will be an array). The first input variable will "reset" the remaining input variables to a standard value when the first variable is changed. The standard values for the input variables are stored in a function in a module. I am attempting to fill the input variable array with the standard values from the function and then display those values on the sheet. I was easily able to do this without arrays but have had no luck in moving everything into arrays.
This is for excel 2010. I previously did not use arrays and created a new variable when needed, however the estimating sheet has grown much larger and it would be better to use arrays at this point. I have googled this question quite a bit, played around with removing and adding parenthesis, changing the type to Variant, trying to set the input variable array to be a variable that is an array (if that makes sense?), and briefly looked into ParamArray but that does not seem applicable here.
Dim BearingDim(1 To 9, 1 To 4, 1 To 8) As Range
Dim arrBearingGeneral(1 To 5, 1 To 8) As Range
Dim Test As Variant
Private Sub Worksheet_Change(ByVal Target As Range)
'Set General Variable array to cells on the worksheet
For i = 1 To 5
For j = 1 To 8
Set arrBearingGeneral(i, j) = Cells(9 + i, 3 + j)
Next j
Next i
'Set Bearing Input Variables to Cells on the Worksheet
For p = 1 To 4
For i = 1 To 9
Select Case p
Case Is = 1
Set BearingDim(i, p, 1) = Cells(16 + i, 4)
Case Is = 2
Set BearingDim(i, p, 1) = Cells(27 + i, 4)
Case Is = 3
Set BearingDim(i, p, 1) = Cells(37 + i, 4)
Case Is = 4
Set BearingDim(i, p, 1) = Cells(49 + i, 4)
End Select
Next i
Next p
'Autopopulate standard input variables based on Bearing Type
inputMD_StdRocker BearingType:=arrBearingGeneral(1, 1), _
arrBearingDim:=BearingDim
End Sub
Sub inputMD_StdRocker(ByVal BearingType As String, ByRef _
arrBearingDim() As Variant)
Dim arrBearingDim(1 To 9, 1 To 4)
Select Case BearingType
Case Is = "MF50-I"
For j = 1 To 2
arrBearingDim(2, j) = 20
arrBearingDim(3, j) = 9
arrBearingDim(4, j) = 1.75
Next j
arrBearingDim(5, 1) = 15
'There are numerous more select case, but those were removed to keep it
'short
End Select
End Sub
The expected output is my "BearingDim" Array will have certain array index values set to a standard value from the "inputMD_StdRocker" function. Then those values will be displayed in the cell that corresponds to the array index.
Currently, I get a compile error "Type Mismatch, Array or User-Defined Type Expected". I have been able to get around the type mismatch by removing the () from "arrBearingDim()" in the function title for "inputMD_StdRocker" however, it will not pass the values back to my "BearingDim" array.
Any help would be greatly appreciated.
This is a partial answer to what (I think) is a misunderstanding you have of how to use arrays. There are a few problems in your code.
First, you're defining a two-dimensional and a three-dimensional array of Ranges when I believe you really only want to store the values captured from the worksheet. (If I'm wrong, then you are never initializing the array of Ranges, so none of the ranges in the array actually point to anything.)
Secondly, it looks as if your initial array arrBearingGeneral is always filled from the same (static) area of the worksheet. If this is so (and you really do want the values from the cells, not an array of Range objects), then you can create a memory-based array (read this website, especially section 19). So the first part of your code can be reduced to
'--- create and populate a memory-based array
Dim bearingDataArea As Range
Dim arrBearingGeneral(1 To 5, 1 To 8) As Variant
Set bearingDataArea = ThisWorkbook.Sheets("Sheet1").Range("D10:K14")
arrBearingGeneral = bearingDataArea.Value
Optionally of course you can calculate the range of your data instead of hard-coding it ("D10:K14"), but this example follows your own example.
While this isn't a complete answer, hopefully it clears up an issue to get you farther down the road.
I'm trying to create a vector in VBA using a for loop. My problem is that VBA doesn't allow me to have a different equation for the first vector coordinate. When trying to run it I get "expected array" as an error message
'radius calculations
r(1) = (al * Log(al) / (al - 1)) * rb ' middle radius of block 1, trying to calculate first entry
'in r-vector, since this equation is different from the rest
r_m(1) = rb 'r_i-1/2 i=1
For i = 2 To n_r
r(i) = al * r(i - 1) ' r_i
r_m(i) = (r(i) - r(i - 1)) / (Log(r(i) / r(i - 1)))
Next i
al and rb is defined as Double (Public Const), while r is defined as a string. I have only used Matlab in the past, and only read intro guides to VBA (VBA for Dummies etc.)
Greatly appreciate all help in the matter
E
VBA doesn't treat strings the same way it treats arrays (like you'd see in other languages). r(1) looks like array syntax to VBA (as can be seen here); therefore, it's going to error out if it's declared as a string.
So, essentially, VBA is interpreting r(1) to mean, "I have an array named r and I want to store something into element number 1". But, instead, it's attempting to do this to an immutable string.
The Split function can be used to turn a string into an array, if that's what you need.
Still, it'll be best if you straight-up declare an array for your vector math.
Dim myArray() As Double
Dim myArray2(10, 10, 10) As Double
The ReDim keyword can be used to resize an array, even within a for loop. (Just don't forget to ReDim Preserve if you need to make sure that the contents don't get wiped during this operation).
I have a 2D array - aArray(1,variable) and want to know how I can For Each through the first rank of the array, ie only read aArray(0 , variable)
This is more for self educational purposes as to how if possible it can be done. I can do it with a for loop:
Dim a As Integer: For a = 0 to ?
Range("A1").Value = aArray(0,a)
Next a
But was interested in using the For Each loop. So far I've got
Dim a As Variant: For Each S In aArray
Range("A1").Value = S
Next a
But it iterates through all the array (0,0) (1,0) (0,1) (1,1) Etc...
You can't do that. You'd have to output the first rank into a new array, and then iterate through that.
There's no good reason to use For Each anyway since it's slower - see: https://support.microsoft.com/en-us/kb/129931
Can anyone help me?
I have been getting a compile error (...: "Expected Array") when dealing with arrays in my Excel workbook.
Basically, I have one 'mother' array (2D, Variant type) and four 'baby' arrays (1D, Double type). The called subroutine creates the publicly declared arrays which my main macro ends up using for display purposes. Unfortunately, the final of the baby arrays craps out (giving the "Compile Error: Expected Array"). Strangely, if I remove this final baby array ('final' - as in the order of declaration/definition) the 2nd to last baby array starts crapping out.
Here is my code:
Public Mother_Array() as Variant, BabyOne_Array(), BabyTwo_Array(), BabyThree_Array(), BabyFour_Array() as Double 'declare may other variables and arrays, too
Sub MainMacro()
'do stuff
Call SunRaySubRoutine(x, y)
'do stuff
Range("blah") = BabyOne_Array: Range("blahblah") = BabyTwo_Array
Range("blahbloh" = BabyThree_Array: Range("blahblue") = BabyFour_Array
End Sub
Sub SunRaySubRoutine(x,y)
n = x * Sheets("ABC").Range("A1").Value + 1
ReDim Mother_Array(18, n) as Variant, BabyOne_Array(n), BabyTwo_Array(n) as Double
ReDim BabyThree_Array(n), BabyFour_Array(n) as Double
'do stuff
For i = 0 to n
BabyOne_Array(i) = Mother_Array(0,i)
BabyTwo_Array(i) = Mother_Array(2,i)
BabyThree_Array(i) = Mother_Array(4,i)
BabyFour_Array(i) = Mother_Array(6,i)
Next
End Sub
I have tried to declare all arrays as the Variant type, but to no avail. I have tried to give BabyFour_Array() a different name, but to no avail.
What's really strange is that even if I comment out the part which makes the BabyFour_Array(), the array still has zero values for each element.
What's also a bit strange is that the first baby array never craps out (although, the 2nd one crapped out once (one time out of maybe 30).
BANDAID: As a temporary fix, I just publicly declared a fifth dummy array (which doesn't get filled or Re-Dimensioned). This fifth array has no actual use besides tricking the system out of having the "Compile Error: Expected Array".
Does anyone know what's causing this "Compile Error: Expected Array" problem with Excel VBA?
Thanks,
Elias
In your global declarations you are only declaring the last baby array as Double. You're declaring the first three as arrays of Variants. But in the subroutine you are Redimming babies one and three as Variants, and two and four as Doubles.
See this Chip Pearson page and scroll down to "Pay Attention To Variables Declared With One Dim Statement."
In VBA when you declare something like:
Dim x, y, z as Long
only z is a Long, the rest are Variants. The correct form is:
Dim x as Long, Y as Long, Z as Long (or Double arrays in your case.)
You can see how this would cause the behavior you describe, i.e., the last one errors, but the others don't.