How to read a dynamic range? - vba

Question

I am trying to create a macro that reads data and does econometrics on the data. At this point I am trying to implement a latent variable MLE estimation.
The data can be of any length, depending on the user input. Suppose there is data in column O and column P. Ex-ante I have no idea how many rows of data exist.
I would like to first read how many data there are and then upload the data into my array variable before I can do any econometrics/statistics on it.
In this problem, the user has 25 data points for each variable. Some other user may enter different data with different number of data points.
In the code below, I am trying to read the variable "D" into an array. I first count the number of non-empty cells and then create an array of that size and try to read the value of the cells into the array. But I am getting a "type mismatch" error.
I've tried both "Variant" and "Array" types. Variant seems to be working but Array is not.
Sub SampleStats()
Dim Rng As String
Dim Var1(1 To 100) As Double
Dim Var2() As Double
Dim Var3 As Variant
Dim NumElements2 As Integer
Dim length2 As Integer
NumElements2 = WorksheetFunction.Count(Range("P:P"))
length2 = NumElements2+1
MsgBox NumElements2
ReDim Var2(1 To NumElements2)
Rng = "P2:P" & length2
MsgBox Rng
Var3 = Range(Rng).Value
MsgBox Var3(1,1)
Var2 = Range(Rng).Value
MsgBox Var2(1,1)
End Sub
My questions are:
Whats the best way to read data when you don't know how long the columns go?
What the best way to store data (Variant or Array or something else) when the final objective is doing some statistics?

Answer 1

First you get the Range with the column of data you want to pass into the array. Second you use the Application.Transpose function on the data and assign it to a Variant to create a 1-dimensional array from the Range.Value property.
If you just assign the range's Value directly to the Variant you will get a 2-dimensional array of N rows x 1 column. Sample code:
Option Explicit
Sub GetRangeToArray()
Dim ws As Worksheet
Dim rngData As Range
Dim varData As Variant
Dim lngCounter As Long
' get worksheet reference
Set ws = ThisWorkbook.Worksheets("Sheet1")
' get the column to analyse - example here is A2:A last row
' so using 1 in column reference to Cells collection
Set rngData = ws.Cells(2, 1).Resize(ws.Cells(ws.Rows.Count, 1).End(xlUp))
' convert range from 2d to 1d array
varData = Application.Transpose(rngData.Value)
' test array
For lngCounter = LBound(varData) To UBound(varData)
Debug.Print varData(lngCounter)
Next lngCounter
End Sub

Answer 2

sub createarraywithoutblanks()
creatary ary, Sheets("Table_Types"), "A":
alternative ary:
BuildArrayWithoutBlanks ary
end sub
Sub creatary(ary As Variant, sh As Worksheet, ltr As String)
Dim x, y, rng As range
ReDim ary(0)
Set rng = sh.range(ltr & "2:" & ltr & sh.range("A10000").End(xlUp).Row).SpecialCells(xlCellTypeVisible)
x = 0
For Each y In rng
ary(x) = y
x = x + 1
ReDim Preserve ary(x)
Next y
End Sub
Function Letter(oSheet As Worksheet, name As String, Optional num As Integer)
If num = 0 Then num = 1
Letter = Application.Match(name, oSheet.Rows(num), 0)
Letter = Split(Cells(, Letter).Address, "$")(1)
End Function
Sub alternative(ary As Variant)
Dim Array_2()
Dim Array_toRemove()
Dim dic As New Scripting.Dictionary
Dim arrItem, x As Long
For Each arrItem In ary
If Not dic.Exists(arrItem) Then
dic.Add arrItem, arrItem
Else
ReDim Preserve Array_toRemove(x)
Array_toRemove(x) = dic.Item(arrItem)
x = x + 1
End If
Next
'For Each arrItem In Array_toRemove
' dic.Remove (arrItem)
'Next arrItem
ary = dic.Keys
End Sub
Sub BuildArrayWithoutBlanks(ary As Variant)
Dim AryFromRange() As Variant, AryNoBlanks() As Variant
Dim Counter As Long, NoBlankSize As Long
'set references and initialize up-front
ReDim AryNoBlanks(0 To 0)
NoBlankSize = 0
'load the range into array
AryFromRange = ary
'loop through the array from the range, adding
'to the no-blank array as we go
For Counter = LBound(AryFromRange) To UBound(AryFromRange)
If AryFromRange(Counter) <> 0 Then
NoBlankSize = NoBlankSize + 1
AryNoBlanks(UBound(AryNoBlanks)) = AryFromRange(Counter)
ReDim Preserve AryNoBlanks(0 To UBound(AryNoBlanks) + 1)
End If
Next Counter
'remove that pesky empty array field at the end
If UBound(AryNoBlanks) > 0 Then
ReDim Preserve AryNoBlanks(0 To UBound(AryNoBlanks) - 1)
End If
'debug for reference
ary = AryNoBlanks
End Sub