How to clear the entire array? - arrays

Question

I have an array like this:
Dim aFirstArray() As Variant
How do I clear the entire array?
What about a collection?

Answer 1

You can either use the Erase or ReDim statements to clear the array. Examples of each are shown in the MSDN documentation. For example:
Dim threeDimArray(9, 9, 9), twoDimArray(9, 9) As Integer
Erase threeDimArray, twoDimArray
ReDim threeDimArray(4, 4, 9)
To remove a collection, you iterate over its items and use the Remove method:
For i = 1 to MyCollection.Count
MyCollection.Remove 1 ' Remove first item
Next i

Answer 2

For deleting a dynamic array in VBA use the instruction Erase.
Example:
Dim ArrayDin() As Integer
ReDim ArrayDin(10) 'Dynamic allocation
Erase ArrayDin 'Erasing the Array
Hope this help!

Answer 3

It is as simple as :
Erase aFirstArray

Answer 4

Find a better use for myself:
I usually test if a variant is empty, and all of the above methods fail with the test. I found that you can actually set a variant to empty:
Dim aTable As Variant
If IsEmpty(aTable) Then
'This is true
End If
ReDim aTable(2)
If IsEmpty(aTable) Then
'This is False
End If
ReDim aTable(2)
aTable = Empty
If IsEmpty(aTable) Then
'This is true
End If
ReDim aTable(2)
Erase aTable
If IsEmpty(aTable) Then
'This is False
End If
this way i get the behaviour i want

Answer 5

[your Array name] = Empty
Then the array will be without content and can be filled again.

Answer 6

ReDim aFirstArray(0)
This will resize the array to zero and erase all data.

Answer 7

i fell into a case where clearing the entire array failed with dim/redim :
having 2 module-wide arrays, Private inside a userform,
One array is dynamic and uses a class module, the other is fixed and has a special type.
Option Explicit
Private Type Perso_Type
Nom As String
PV As Single 'Long 'max 1
Mana As Single 'Long
Classe1 As String
XP1 As Single
Classe2 As String
XP2 As Single
Classe3 As String
XP3 As Single
Classe4 As String
XP4 As Single
Buff(1 To 10) As IPicture 'Disp
BuffType(1 To 10) As String
Dances(1 To 10) As IPicture 'Disp
DancesType(1 To 10) As String
End Type
Private Data_Perso(1 To 9, 1 To 8) As Perso_Type
Dim ImgArray() As New ClsImage 'ClsImage is a Class module
And i have a sub declared as public to clear those arrays (and associated run-time created controls) from inside and outside the userform like this :
Public Sub EraseControlsCreatedAtRunTime()
Dim i As Long
On Error Resume Next
With Me.Controls 'removing all on run-time created controls of the Userform :
For i = .Count - 1 To 0 Step -1
.Remove i
Next i
End With
Err.Clear: On Error GoTo 0
Erase ImgArray, Data_Perso
'ReDim ImgArray() As ClsImage ' i tried this, no error but wouldn't work correctly
'ReDim Data_Perso(1 To 9, 1 To 8) As Perso_Type 'without the erase not working, with erase this line is not needed.
End Sub
note : this last sub was first called from outside (other form and class module) with Call FormName.SubName but had to replace it with Application.Run FormName.SubName , less errors, don't ask why...

Answer 8

Only use Redim statement
Dim aFirstArray() As Variant
Redim aFirstArray(nRows,nColumns)