FOR Cycle inside a UDF in Excel not working - excel

Question

I'm currently programming an Excel Function which should return the average of the last 5 non-empty positions of an array. To do that I want to go through the array while inside the function as follows:
Function AVERAGE_LAST_5(rng As Range) As Long
Dim x As Integer, i As Integer, j As Integer, sum As Integer
Dim myArr() As Variant
myArr() = Application.Transpose(Application.Transpose(rng))
x = rng.Count
i = 0:: j = 0:: sum = 0
For i = x To 1 Step -1
If myArr(x).Value <> 0 Then
sum = sum + myArr(x)
j = j + 1
Else
End If
If j = 5 Then Stop
x = x - 1
Next
AVERAGE_LAST_5 = sum / 5
End Function
Problem: the for loop doesn't work, when reaching the first if the program aborts.
Does anyone has had the same problem?
Can anyone help me with it?

Answer 1

myarr will be a two-dimensional array, and not a range. You will need to provide both dimensions:
If isarray(myarr) then
for i = ubound(myarr,1) to lbound(myarr,1) step -1
for j = ubound(myarr,2) to lbound (myarr,2) step -1
if myarr(i,j) <> 0 then
K=k+1
Mysum = mysum + myarr(I,j)
Endif
Next j
Next i
Else ‘ single value
mysum =myarr(I,j)
Endif

Answer 2

Arrays Are Faster
Final Version (Hopefully)
This version additionally has the NumberOfLastValues argument (Required) so you can choose how many values will be summed up and it is shortened with the GoSub...Return statement since the If statement is the same for by rows and by columns.
For some other details look in the First Version below.
Usage
In VBA:
Sub LastAverage()
Debug.Print AvgLast(Range("B4:G14"), 5)
End Sub
In Excel:
=AvgLast(B4:G14,5)
Function AvgLast(SearchRange As Range, ByVal NumberOfLastValues As Long, _
Optional ByVal Row_0_Column_1 As Integer = 0) As Double
Dim vntRange As Variant ' Range Array
Dim i As Long ' Range Array Rows Counter
Dim j As Integer ' Range Array Columns Counter
Dim k As Long ' Values Counter
Dim dblSum As Double ' Values Accumulator
If SearchRange Is Nothing Then Exit Function
vntRange = SearchRange.Value
If Row_0_Column_1 = 0 Then
' By Row
For i = UBound(vntRange) To 1 Step -1
For j = UBound(vntRange, 2) To 1 Step -1
GoSub Calc
Next
Next
Else
' By Column
For j = UBound(vntRange, 2) To 1 Step -1
For i = UBound(vntRange) To 1 Step -1
GoSub Calc
Next
Next
End If
TiDa:
If k > 0 Then
AvgLast = dblSum / k
End If
Exit Function
Calc:
If vntRange(i, j) <> "" And IsNumeric(vntRange(i, j)) Then
k = k + 1
dblSum = dblSum + vntRange(i, j)
If k = NumberOfLastValues Then GoTo TiDa
End If
Return
End Function
First Version
It will return the average if there is at least 1 value and at most 5 values, otherwise it will return 0.
The Row_0_Column_1 arguments parameter is by default 0 and means that the search is done by row (first loop). If it is 1, then the search is done by column (second loop).
The basics are that the range is pasted (depsited) into an array and then the array is searched for existing 'numeric' values and not "" values that are summed up and when reaching the fifth value it 'jumps' out of the loop and divides the sum by 5.
Function AvgLast5(SearchRange As Range, Optional Row_0_Column_1 As Integer = 0) _
As Double
Dim vntRange As Variant ' Range Array
Dim i As Long ' Range Array Rows Counter
Dim j As Integer ' Range Array Columns Counter
Dim k As Long ' Values Counter
Dim dblSum As Double ' Values Accumulator
If SearchRange Is Nothing Then Exit Function
vntRange = SearchRange.Value
If Row_0_Column_1 = 0 Then
' By Row
For i = UBound(vntRange) To 1 Step -1
For j = UBound(vntRange, 2) To 1 Step -1
If vntRange(i, j) <> "" And IsNumeric(vntRange(i, j)) Then
k = k + 1
dblSum = dblSum + vntRange(i, j)
If k = 5 Then GoTo TiDa
End If
Next
Next
Else
' By Column
For j = UBound(vntRange, 2) To 1 Step -1
For i = UBound(vntRange) To 1 Step -1
If vntRange(i, j) <> "" And IsNumeric(vntRange(i, j)) Then
k = k + 1
dblSum = dblSum + vntRange(i, j)
If k = 5 Then GoTo TiDa
End If
Next
Next
End If
TiDa:
If k > 0 Then
AvgLast5 = dblSum / k
End If
End Function

Answer 3

after a couple of tough days at work I've finally got some time to improve my function taking your tips on board.
I've made some changes to enable the function to deal either with 1-Row or 1-Column Ranges. Basic Error handling was also added and a function discripton is as well available (under the FX Excel button).
Feel free to comment and/or use the code.
Here the result:
Function AVERAGE_LAST_N(rng As Range, N As Integer)
Dim NrN As Integer, NrR As Integer, NrC As Integer
Dim i As Integer, j As Integer
Dim sum As Double
Dim myArr As Variant
NrN = rng.Count 'Number of array positions
NrR = rng.Rows.Count 'Number of Rows in the array
NrC = rng.Columns.Count 'Number of Rows in the array
i = 0:: j = 0:: sum = 0 'Counters
'####################################################'
'## Transpose Range into array if row or if column ##'
'####################################################'
If rng.Rows.Count > 1 And rng.Columns.Count = 1 Then 'Transpose a Column Range into an Array
myArr = Application.Transpose(rng)
ElseIf rng.Rows.Count = 1 And rng.Columns.Count > 1 Then 'Transpose a Row Range into an Array
myArr = Application.Transpose(Application.Transpose(rng))
ElseIf rng.Rows.Count > 1 And rng.Columns.Count > 1 Then 'Retunrs an Error if Range is a Matrix *ERR_002*
AVERAGE_LAST_N = "ERR_002"
Exit Function
End If
'####################################################'
'## Transpose Range into array if row or if column ##'
'####################################################'
'################'
'## Start Main ##'
'################'
For i = NrN To 1 Step -1
If IsNumeric(myArr(NrN)) Then
sum = sum + myArr(NrN)
j = j + 1
End If
If j = N Then Exit For
NrN = NrN - 1
Next
AVERAGE_LAST_N = sum / N
'##############'
'## End Main ##'
'##############'
'####################'
'## Error Debuging ##'
'####################'
If j < N Then
AVERAGE_LAST_N = "ERR_001"
Exit Function
End If
'####################'
'## Error Debuging ##'
'####################'
End Function
Sub DescribeFunction()
Dim FuncName As String
Dim FuncDesc As String
Dim Category As String
Dim ArgDesc(1) As String
FuncName = "AVERAGE_LAST_N"
FuncDesc = "Returns the average of the last N non-empty values in the selected Range"
Category = 14 'Text category
ArgDesc(0) = "Range that contains the values" & Chr(10) & _
"ERR_001 - There are not enought non-empty or null values in the range" & Chr(10) & _
"ERR_002 - Selected range is a matrix and not a row or column range"
ArgDesc(1) = "Dimention of the sample" & Chr(10) & _
"ERR_001 - There are not enought non-empty or null values in the range" & Chr(10) & _
"ERR_002 - Selected range is a matrix and not a row or column range"
Application.MacroOptions _
Macro:=FuncName, _
Description:=FuncDesc, _
Category:=Category, _
ArgumentDescriptions:=ArgDesc
End Sub
'#######################################################################################
' ###############################################
' ############# Error DB ##############
' ###############################################
'
'
' ERR_001 - There are not enought non-empty values in the range
' ERR_002 - Selected range is a matrix and not a row or column range
'
Rafa