I have the next code:
Function findRanges(keyword) As Variant()
Dim foundRanges(), rngSearch As Range
Dim i, foundCount As Integer
i = 0
foundCount = 0
ReDim foundRanges(0)
Set rngSearch = ActiveDocument.Range
Do While rngSearch.Find.Execute(FindText:=keyword, MatchWholeWord:=True, Forward:=True) = True
Set foundRanges(i) = rngSearch.Duplicate
i = i + 1
ReDim Preserve foundRanges(UBound(foundRanges) + 1)
rngSearch.Collapse Direction:=wdCollapseEnd
Loop
ReDim Preserve foundRanges(UBound(foundRanges) - 1)
findRanges = foundRanges
End Function
And:
Sub test()
Dim rngIAM_Code() As Range
...
Dim rngIAM_Title() As Range
rngIAM_Code = findRanges("IAM_Code")
...
rngIAM_Title = findRanges("IAM_Title")
End Sub
What is very confuding is that sometimes the compiler says "Can't assign to array" and sometimes it works fine. For example, when I only try to search one value and populate one array, the code works. When I try to populate both array, there is an error "Can't assign to an array". I can then switch lines of code like this:
rngIAM_Title = findRanges("IAM_Title")
...
rngIAM_Code = findRanges("IAM_Code")
And then the error happens with another array. The error can happen anywhere: on the first line, in the middle, or in the end, but it is consistent as long as I don't move lines. And again, if I leave only one-two lines of code with arrays in sub "test"everything works fine.
The following works for me.
In this code, every object variable is explicitly assigned a type. In VBA, every variable must be typed, else it's assigned the type Variant by default. In the following declaration line, for example, foundRanges() is of type Variant because it's not followed by As with a data type. The same with i in the next line of code in the question.
Dim foundRanges(), rngSearch As Range
And since the arrays in the calling procedure are of type Range the function should return the same type.
I also took the liberty of passing the Document object to the function as, conceivably, some day the document in question might not be ActiveDocument but a Document object assigned using Documents.Open or Documents.Add. If this is not desired it can be changed back, but not relying on ActiveDocument is more reliable...
Additionally, I added the Wrap parameter to Find.Execute - it's always a good idea to specify that when executing Find in a loop to prevent the search from starting again at the beginning of the document (wdFindContinue).
Sub testRangesInArrays()
Dim rngIAM_Code() As Range
Dim rngIAM_Title() As Range
rngIAM_Code = findRanges("You", ActiveDocument)
rngIAM_Title = findRanges("change", ActiveDocument)
End Sub
Function findRanges(keyword As String, doc As Word.Document) As Range()
Dim foundRanges() As Range, rngSearch As Range
Dim i As Integer, foundCount As Integer
i = 0
foundCount = 0
ReDim foundRanges(0)
Set rngSearch = doc.content
Do While rngSearch.Find.Execute(findText:=keyword, MatchWholeWord:=True, _
Forward:=True, wrap:=wdFindStop) = True
Set foundRanges(i) = rngSearch.Duplicate
ReDim Preserve foundRanges(UBound(foundRanges) + 1)
i = i + 1
rngSearch.Collapse Direction:=wdCollapseEnd
Loop
findRanges = foundRanges
End Function
Here is an alternative based on a Collection instead of an Array:
I used also included Cindys Input regarding passing the document and adding wrap.
I don't exactly know what the you use the return value for, but in general a collection is a bit more flexible than an Array.
I also removed the underscores since they indicate a function of an implemented Interface and may cause problems later down the line. are used when implementing an Interface (improves readability).
As explained here you can use wrap or collapse to prevent a continuous Loop.
Option Explicit
Sub test()
Dim rngIAMCode As Collection
Dim rngIAMTitle As Collection
Set rngIAMCode = findRanges("IAM_Code", ActiveDocument)
Set rngIAMTitle = findRanges("IAM_Title", ActiveDocument)
Debug.Print "Code found : " & rngIAMCode.Count & " Times."
Debug.Print "Title found : " & rngIAMTitle.Count & " Times."
End Sub
Function findRanges(ByVal keyword As String, doc As Document) As Collection
Set findRanges = New Collection
Dim rngSearch As Range
Set rngSearch = doc.Content
With rngSearch.Find
.Text = keyword
.MatchWholeWord = True
.Forward = True
.Wrap = wdFindStop
While .Execute
findRanges.Add rngSearch.Duplicate
rngSearch.Collapse Direction:=wdCollapseEnd
Wend
End With
End Function
Situation:
I have a function, RemoveEmptyArrRowCol, which accepts two arguments, one of which is an array (tempArr).
When the second argument was a Long everything was fine. When I changed the second argument to a String (and the associated call variable) I got:
Type mismatch (Error 13)
So in the below code examples:
Test1 runs fine
Test2 fails
Questions:
1) Why is the behaviour different between the two?
2) How do I fix the second version so it behaves as per the first?
3) How will I future proof this for when I pass a dictionary value (array) as the 1st parameter, rather than reading directly from the worksheet?
What I have tried:
This appears to be a common question on SO and I have looked at a number of these questions; some of which I have put as references at the bottom of this question. I still, however, have not resolved why the first of these two sub works, but the second does not?
I played around with different combinations of:
Adding extra brackets
Explicitly declaring the type of tempArr: Dim tempArr() As Variant
Changing part of the function signature: ByRef tempArr() As Variant
After looking at #Fionnuala's answer to this question, MS Access/VBA type mismatch when passing arrays to function/subroutine, I decided to try using Call:
Call RemoveEmptyArrRowCol2(ws.Range("C4:I129").Value, tempStr)
This compiled but means I would need to change other parts of my code to ensure tempArr is correctly populated. If I were to do it this way, I might as well convert the function to a procedure.
As is, the flow is that I populate tempArr, in the test example, direct from the sheet and then hand off to another sub i.e.
tempArr = RemoveEmptyArrRowCol(ws.Range("C4:I129").Value, tempStr)
ArrayToSheet wb.Worksheets("Test").Range("A1"), tempArr
Note re: Question 3:
In the final version, I will be passing an array, pulled from a dictionary, as the first parameter i.e.
tempArr = RemoveEmptyArrRowCol( ArrayDict(tempStr), tempStr)
Working version:
Option Explicit
Public Sub Test1()
Dim tempArr() 'variant
Init
Dim tempStr As String: tempStr = "Response Times"
tempArr = RemoveEmptyArrRowCol(ws.Range("C4:I129").Value, categoryDict(tempStr & "Cols"))
End Sub
Private Function RemoveEmptyArrRowCol(ByRef tempArr As Variant, ByVal nCols As Long) As Variant
End Function
Failing version:
Public Sub Test2()
Dim tempArr()
Init
Dim tempStr As String: tempStr = "Response Times"
tempArr = RemoveEmptyArrRowCol2(ws.Range("C4:I129").Value, tempStr)
End Sub
Private Function RemoveEmptyArrRowCol2(ByRef tempArr As Variant, ByVal tempStr As String) As Variant
End Function
Example of the current full function:
Private Function RemoveEmptyArrRowCol(ByRef tempArr As Variant, ByVal tempStr As String) As Variant
Dim i As Long
Dim j As Long
Dim counter As Long
counter = 0
Dim tempArr2()
Dim totCol As Long
Dim adjColTotal As Long
totCol = categoryDict(tempStr & "Cols")
adjColTotal = categoryDict(tempStr & "ColsAdj")
Select Case tempStr
Case "ResponseTimes", "NoCCPR"
ReDim tempArr2(1 To 1000, 1 To adjColTotal)
For i = 1 To UBound(tempArr, 1)
If tempArr(i, 2) <> vbNullString Then 'process row
counter = counter + 1 'load row to temp array (counter becomes row count)
For j = 1 To totCol
Select Case j
Case Is < 4
tempArr2(counter, j) = tempArr(i, j)
Case Is > 4
tempArr2(counter, j - 1) = tempArr(i, j)
End Select
Next j
End If
Next i
RemoveEmptyArrRowCol = RedimArrDimOne(tempArr2, adjColTotal, counter)
Case "Incidents"
End Select
End Function
Additional references:
1) Passing arrays to functions in vba
2) Passing array to function returns compile error
3) Type mismatch error when passing arrays to a function in excel vba
4) Should I use Call keyword in VBA
It really depends on your input and output, e.g. what is in the RemoveEmptyArrRowCol2 function. This is an option, in which tempStr as String is not failing:
Public Sub Test2()
Dim tempArr()
Dim tempStr As String: tempStr = "Response Times"
tempArr = RemoveEmptyArrRowCol2(Range("C4:I129").Value, tempStr)
End Sub
Private Function RemoveEmptyArrRowCol2(ByRef tempArr As Variant, _
ByVal tempStr As String) As Variant
RemoveEmptyArrRowCol2 = Array(1, 2)
End Function
E.g., if you remove the returning value (Array(1,2), it fails) but it should fail, because it does not return anything.
Define "Dim tempArr As Variant" not as Variant-Array with "()"
Please show us your function "categoryDict" and "ArrayDict"
"Call" is not nessesary!
You access Values as follows:
Dim r As Long
Dim c As Long
For r = 1 To UBound(tempArr, 1)
For c = 1 To UBound(tempArr, 2)
Debug.Print tempArr(r, c)
Next
Next
Let's say I have the following Array, arr that contains a maximum of 20 substrings. In this example, the array will have 4 substrings:
arr = {"AAAA: 1234567" , "BBBB: 2345678" , "CCCC: 98765432" , "DDDD: 87654321"}
Note: Capitalization is not important.
I am needing assistance with finding a substring inside an array (again, up to 20 strings possible), that Starts With CCCC:, and then assigning that entire string to it's own variable, let's call it Var1.
I understand I could assign Var1 = arr(2), but I need to figure out how to determine the index number in the array that meets my criteria.
What I would really appreciate (although any method I will be happy with), is making a stand alone function such as:
Function ArrayIndex(ArrayInput as Variant, StartsWith as String) as Byte
'Arguments Here
End Function
Then I could just use this in my Subroutine:
Var1 = arr(ArrayIndex(arr, "CCCC:"))
Update 1
Here is a snippet of my current code
Sub T_Report
'<Shortcut = Shift+Ctrl+T>
Dim Data as String, DataArray as Variant
With ActiveSession
.Copy 0, 2, 80, 21 'Just a big block of text with multiple lines, copied to clipboard
Data = Clipboard 'Set Data to the clipboard value
DataArray = Split(Data,vbCrLf) 'This is "Data" in an Array, separated by line breaks
'Just checking to see if the Array was successful (it is)
Debug.Print DataArray(0) & vbNL & DataArray(1) & vbNL & DataArray(2) & _
vbNL & DataArray(3) & vbNL & DataArray(4) & vbNL & vbNL
'Misc code here
Dim sF1 as String, sF2 as String, sF3 as String
Dim Rslt1 as String, Rslt2 as String, Rslt3 as String
sF1 = "Field1:"
sF2 = "Field2:"
sF3 = "Field3:"
MsgBox DataArray(0) ' This works fine, giving me first substring
Rslt1 = FindMyString(sF1, DataArray)
' Misc Code
End With
End Sub
However, when I use the following function, I get Type Mismatch error on the MsgBox arr(0) line, although it should be giving me the very first substring of DataArray in the above sub (should be an exact match, the array has not been modified).. However, when I do MsgBox DataArray(0) above, I do get the first substring.
Private Function FindMyString(strToFind As String, ParamArray arr() As Variant) As String
Dim i As Integer
Dim iLen As Integer
Dim strArr As String
FindMyString = "" ' Returns Blank String if not found
' I get type mismatch here (Doesn't appear Array from sub loaded into this function)
MsgBox arr(0)
iLen = Len(strToFind)
For i = 0 To UBound(arr)
strArr = CStr(arr(i))
If strToFind = Left$(strArr, iLen) Then
FindMyString = strArr
Exit Function
End If
Next i
End Function
EDIT - FIX YOUR ARRAY LOAD
Change this (it MUST give you an error!):
arr = {"AAAA: 1234567" , "BBBB: 2345678" , "CCCC: 98765432" , "DDDD: 87654321"}
To This:
Dim arr As Variant
arr = Split("AAAA: 1234567,BBBB: 2345678,CCCC: 98765432,DDDD: 87654321", ",")
If you want to use a function to do your bidding you can pass an array of data using the ParamArray type. It has to be the last parameter in your function
This should do what you want:
Private Function FindMyString(strToFind as string, ParamArray arr() As Variant) As String
Dim i As Integer
Dim iLen as Integer
Dim strArr as String
FindMyString = "" ' Returns Blank String if not found '
Debug.Print arr(0)(0) ' Print first element of array
iLen = Len(strToFind)
For i = 0 To UBound(arr(0))
strArr = CStr(arr(0)(i))
If strToFind = Left$(strArr, iLen) Then
FindMyString = strArr
Exit Function
End If
Next i
End Function
In your example you can test it by:
Var1 = FindMyString("CCCC:", arr)
I am having some trouble getting a function I have been writing to work properly. I need it to take an array that is sized 1 to x, and transfer it to a new array which is sized 0 to x-1. I would think it would work just like this:
Private Function ShiftDownArray(theArray() As String) As String()
Dim a As Integer
ReDim ShiftDownArray(LBound(theArray) - 1 To UBound(theArray) - 1)
For a = LBound(theArray) To UBound(theArray)
ShiftDownArray(a - 1) = theArray(a)
Next a
End Function
But I get a compile error: Function call on left-hand side of assignment must return Variant or Object. The documentation on this error essentially says delete that line to make it work, which doesn't point me in the right direction. I have tried changing the type to variant, but it starts a chain reaction of needing to change array type from string to variant, and it leads to issues in other parts of my program.
Is there any way to approach this that will allow me to retain the string array type? Thanks
You can pass arrays of most types as a Variant between methods and procedures in VBA
Private Function ShiftDownArray(ByRef theArray As Variant) As Variant
Dim i As Integer
ReDim x(0 To UBound(theArray) - 1) As Variant
For i = 0 To UBound(x)
x(i) = theArray(i + 1)
Next i
ShiftDownArray = x
End Function
But more importantly - why would you want to do this anyway? You can just -/+ 1 to the index in the original array?
Is this what you are looking for:
Public Sub ShiftArrayTest()
'Make an 1-bound array
Dim arr1() As String, N As Long, i As Long
N = 10
ReDim arr1(1 To N)
For i = 1 To N
arr1(i) = CStr(i)
Next i
'Now for the shift
Dim arr2() As String
arr2 = ShiftArray(arr1)
End Sub
Public Function ShiftArray(ByRef theArray() As String) As String()
'Now for the shift
Dim i1 As Long, N As Long, i As Long, res() As String
i1 = LBound(theArray): N = UBound(theArray) - i1 + 1
ReDim res(0 To N - 1)
For i = 0 To N - 1
res(i) = theArray(i1 + i)
Next i
ShiftArray = res
End Function
What I am doing here is taking any array and converting it into a 0-bound array.
The Error is most probably in this line: 'ReDim ShiftDownArray(LBound(theArray) - 1 To UBound(theArray) - 1)'
It looks like you're recursively calling itself, which seems odd given there isn't a base case.
See the following example as provided by this website. The gist of it is that it will skip the first element and copy everything over 'to the left'.
Function Array_Shift(arr As Variant) As Variant
' http://www.php.net/manual/en/function.array-shift.php
Dim tempArray As Variant
Dim i As Long
tempArray = arr
' shift elements one position up
' by skipping the first element of the source array
For i = LBound(tempArray) To UBound(tempArray) - 1
tempArray(i) = tempArray(i + 1)
Next i
' remove last element
' which is now empty
ReDim Preserve tempArray(LBound(tempArray) To UBound(tempArray) - 1)
Array_Shift = tempArray
End Function
The trouble is not with passing an array of strings as a parameter - you can pass arrays of any type, as far as I'm aware. However, assigning a value to ShiftDownArray(a - 1) is ambiguous as you could be accessing the a-1th element of the array or passing a - 1 as a parameter to the ShiftDownArray() function.
The Function call on left-hand side of assignment must return Variant or Object. error message hints to this. You are calling the ShiftDownArray() function rather than accessing the array. The compiler knows you are going to assign something to the value returned by the function (because it is followed by an =) but doesn't know the type as it hasn't yet evaluated theArray(a). To ensure that the assignment can complete regardless of the type of theArray(a), the compiler tries to make sure that ShiftDownArray() returns a Variant or Object to which anything can be assigned.
To avoid this error you can create a temporary array which can be accessed in the conventional manner and assign that array to ShiftDownArray to return from the function.
The following code shows this:
Private Function ShiftDownArray(theArray() As String) As String()
ReDim tempArray(LBound(theArray) - 1 To UBound(theArray) - 1) As String
Dim i As Integer
For i = LBound(tempArray) To UBound(tempArray)
tempArray(i) = theArray(i + 1)
Next i
ShiftDownArray = tempArray
End Function
Passing an undimensioned array to the VB6's Ubound function will cause an error, so I want to check if it has been dimensioned yet before attempting to check its upper bound. How do I do this?
Note: the code has been updated, the original version can be found in the revision history (not that it is useful to find it). The updated code does not depend on the undocumented GetMem4 function and correctly handles arrays of all types.
Note for VBA users: This code is for VB6 which never got an x64 update. If you intend to use this code for VBA, see https://stackoverflow.com/a/32539884/11683 for the VBA version. You will only need to take the CopyMemory declaration and the pArrPtr function, leaving the rest.
I use this:
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
(ByRef Destination As Any, ByRef Source As Any, ByVal length As Long)
Private Const VT_BYREF As Long = &H4000&
' When declared in this way, the passed array is wrapped in a Variant/ByRef. It is not copied.
' Returns *SAFEARRAY, not **SAFEARRAY
Public Function pArrPtr(ByRef arr As Variant) As Long
'VarType lies to you, hiding important differences. Manual VarType here.
Dim vt As Integer
CopyMemory ByVal VarPtr(vt), ByVal VarPtr(arr), Len(vt)
If (vt And vbArray) <> vbArray Then
Err.Raise 5, , "Variant must contain an array"
End If
'see https://msdn.microsoft.com/en-us/library/windows/desktop/ms221627%28v=vs.85%29.aspx
If (vt And VT_BYREF) = VT_BYREF Then
'By-ref variant array. Contains **pparray at offset 8
CopyMemory ByVal VarPtr(pArrPtr), ByVal VarPtr(arr) + 8, Len(pArrPtr) 'pArrPtr = arr->pparray;
CopyMemory ByVal VarPtr(pArrPtr), ByVal pArrPtr, Len(pArrPtr) 'pArrPtr = *pArrPtr;
Else
'Non-by-ref variant array. Contains *parray at offset 8
CopyMemory ByVal VarPtr(pArrPtr), ByVal VarPtr(arr) + 8, Len(pArrPtr) 'pArrPtr = arr->parray;
End If
End Function
Public Function ArrayExists(ByRef arr As Variant) As Boolean
ArrayExists = pArrPtr(arr) <> 0
End Function
Usage:
? ArrayExists(someArray)
Your code seems to do the same (testing for SAFEARRAY** being NULL), but in a way which I would consider a compiler bug :)
I just thought of this one. Simple enough, no API calls needed. Any problems with it?
Public Function IsArrayInitialized(arr) As Boolean
Dim rv As Long
On Error Resume Next
rv = UBound(arr)
IsArrayInitialized = (Err.Number = 0)
End Function
Edit: I did discover a flaw with this related to the behavior of the Split function (actually I'd call it a flaw in the Split function). Take this example:
Dim arr() As String
arr = Split(vbNullString, ",")
Debug.Print UBound(arr)
What is the value of Ubound(arr) at this point? It's -1! So, passing this array to this IsArrayInitialized function would return true, but attempting to access arr(0) would cause a subscript out of range error.
Here's what I went with. This is similar to GSerg's answer, but uses the better documented CopyMemory API function and is entirely self-contained (you can just pass the array rather than ArrPtr(array) to this function). It does use the VarPtr function, which Microsoft warns against, but this is an XP-only app, and it works, so I'm not concerned.
Yes, I know this function will accept anything you throw at it, but I'll leave the error checking as an exercise for the reader.
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
(pDst As Any, pSrc As Any, ByVal ByteLen As Long)
Public Function ArrayIsInitialized(arr) As Boolean
Dim memVal As Long
CopyMemory memVal, ByVal VarPtr(arr) + 8, ByVal 4 'get pointer to array
CopyMemory memVal, ByVal memVal, ByVal 4 'see if it points to an address...
ArrayIsInitialized = (memVal <> 0) '...if it does, array is intialized
End Function
I found this:
Dim someArray() As Integer
If ((Not someArray) = -1) Then
Debug.Print "this array is NOT initialized"
End If
Edit: RS Conley pointed out in his answer that (Not someArray) will sometimes return 0, so you have to use ((Not someArray) = -1).
Both methods by GSerg and Raven are undocumented hacks but since Visual BASIC 6 is no longer being developed then it is not a issue. However Raven's example doesn't work on all machines. You have to test like this.
If (Not someArray) = -1 Then
On some machines it will return a zero on others some large negative number.
In VB6 there is a function called "IsArray", but it does not check if the array has been initialized. You will receive Error 9 - Subscript out of range if you attempt to use UBound on an uninitialized array. My method is very similar to S J's, except it works with all variable types and has error handling. If a non-array variable is checked, you will receive Error 13 - Type Mismatch.
Private Function IsArray(vTemp As Variant) As Boolean
On Error GoTo ProcError
Dim lTmp As Long
lTmp = UBound(vTemp) ' Error would occur here
IsArray = True: Exit Function
ProcError:
'If error is something other than "Subscript
'out of range", then display the error
If Not Err.Number = 9 Then Err.Raise (Err.Number)
End Function
Since wanted comment on here will post answer.
Correct answer seems is from #raven:
Dim someArray() As Integer
If ((Not someArray) = -1) Then
Debug.Print "this array is NOT initialized"
End If
When documentation or Google does not immediately return an explanation people tend to call it a hack.
Although what seems to be the explanation is that Not is not only a Logical, it is also a Bitwise operator, so it handles the bit representation of structures, rather than Booleans only.
For example of another bitwise operation is here:
Dim x As Integer
x = 3 And 5 'x=1
So the above And is also being treated as a bitwise operator.
Furthermore, and worth to check, even if not the directly related with this,
The Not operator can be overloaded, which means that a class or
structure can redefine its behavior when its operand has the type of
that class or structure.
Overloading
Accordingly, Not is interpreting the array as its bitwise representation and it distinguishes output when array is empty or not like differently in the form of signed number. So it can be considered this is not a hack, is just an undocumentation of the array bitwise representation, which Not here is exposing and taking advantage of.
Not takes a single operand and inverts all the bits, including the
sign bit, and assigns that value to the result. This means that for
signed positive numbers, Not always returns a negative value, and for
negative numbers, Not always returns a positive or zero value.
Logical Bitwise
Having decided to post since this offered a new approach which is welcome to be expanded, completed or adjusted by anyone who has access to how arrays are being represented in their structure. So if anyone offers proof it is actually not intended for arrays to be treated by Not bitwise we should accept it as not a hack and actually as best clean answer, if they do or do not offer any support for this theory, if it is constructive comment on this is welcome of course.
This is modification of raven's answer. Without using API's.
Public Function IsArrayInitalized(ByRef arr() As String) As Boolean
'Return True if array is initalized
On Error GoTo errHandler 'Raise error if directory doesnot exist
Dim temp As Long
temp = UBound(arr)
'Reach this point only if arr is initalized i.e. no error occured
If temp > -1 Then IsArrayInitalized = True 'UBound is greater then -1
Exit Function
errHandler:
'if an error occurs, this function returns False. i.e. array not initialized
End Function
This one should also be working in case of split function.
Limitation is you would need to define type of array (string in this example).
When you initialite the array put an integer or boolean with a flag = 1. and query this flag when you need.
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
Private Declare Function ArrPtr Lib "msvbvm60" Alias "VarPtr" (arr() As Any) As Long
Private Type SafeArray
cDims As Integer
fFeatures As Integer
cbElements As Long
cLocks As Long
pvData As Long
End Type
Private Function ArrayInitialized(ByVal arrayPointer As Long) As Boolean
Dim pSafeArray As Long
CopyMemory pSafeArray, ByVal arrayPointer, 4
Dim tArrayDescriptor As SafeArray
If pSafeArray Then
CopyMemory tArrayDescriptor, ByVal pSafeArray, LenB(tArrayDescriptor)
If tArrayDescriptor.cDims > 0 Then ArrayInitialized = True
End If
End Function
Usage:
Private Type tUDT
t As Long
End Type
Private Sub Form_Load()
Dim longArrayNotDimmed() As Long
Dim longArrayDimmed(1) As Long
Dim stringArrayNotDimmed() As String
Dim stringArrayDimmed(1) As String
Dim udtArrayNotDimmed() As tUDT
Dim udtArrayDimmed(1) As tUDT
Dim objArrayNotDimmed() As Collection
Dim objArrayDimmed(1) As Collection
Debug.Print "longArrayNotDimmed " & ArrayInitialized(ArrPtr(longArrayNotDimmed))
Debug.Print "longArrayDimmed " & ArrayInitialized(ArrPtr(longArrayDimmed))
Debug.Print "stringArrayNotDimmed " & ArrayInitialized(ArrPtr(stringArrayNotDimmed))
Debug.Print "stringArrayDimmed " & ArrayInitialized(ArrPtr(stringArrayDimmed))
Debug.Print "udtArrayNotDimmed " & ArrayInitialized(ArrPtr(udtArrayNotDimmed))
Debug.Print "udtArrayDimmed " & ArrayInitialized(ArrPtr(udtArrayDimmed))
Debug.Print "objArrayNotDimmed " & ArrayInitialized(ArrPtr(objArrayNotDimmed))
Debug.Print "objArrayDimmed " & ArrayInitialized(ArrPtr(objArrayDimmed))
Unload Me
End Sub
Based on all the information I read in this existing post this works the best for me when dealing with a typed array that starts as uninitialized.
It keeps the testing code consistent with the usage of UBOUND and It does not require the usage of error handling for testing.
It IS dependent on Zero Based Arrays (which is the case in most development).
Must not use "Erase" to clear the array. use alternative listed below.
Dim data() as string ' creates the untestable holder.
data = Split(vbNullString, ",") ' causes array to return ubound(data) = -1
If Ubound(data)=-1 then ' has no contents
' do something
End If
redim preserve data(Ubound(data)+1) ' works to increase array size regardless of it being empty or not.
data = Split(vbNullString, ",") ' MUST use this to clear the array again.
The easiest way to handle this is to insure that the array is initialized up front, before you need to check for the Ubound. I needed an array that was declared in the (General) area of the form code.
i.e.
Dim arySomeArray() As sometype
Then in the form load routine I redim the array:
Private Sub Form_Load()
ReDim arySomeArray(1) As sometype 'insure that the array is initialized
End Sub
This will allow the array to be re-defined at any point later in the program.
When you find out how big the array needs to be just redim it.
ReDim arySomeArray(i) As sometype 'i is the size needed to hold the new data
The title of the question asks how to determine if an array is initialized, but, after reading the question, it looks like the real problem is how to get the UBound of an array that is not initialized.
Here is my solution (to the the actual problem, not to the title):
Function UBound2(Arr) As Integer
On Error Resume Next
UBound2 = UBound(Arr)
If Err.Number = 9 Then UBound2 = -1
On Error GoTo 0
End Function
This function works in the following four scenarios, the first three that I have found when Arr is created by an external dll COM and the fourth when the Arr is not ReDim-ed (the subject of this question):
UBound(Arr) works, so calling UBound2(Arr) adds a little overhead, but doesn't hurt much
UBound(Arr) fails in in the function that defines Arr, but succeeds inside UBound2()
UBound(Arr) fails both in the function that defines Arr and in UBound2(), so the error handling does the job
After Dim Arr() As Whatever, before ReDim Arr(X)
For any variable declared as an array, you can easily check if the array is initialized by calling the SafeArrayGetDim API. If the array is initialized, then the return value will be non-zero, otherwise the function returns zero.
Note that you can't use this function with variants that contain arrays. Doing so will cause a Compile error (Type mismatch).
Public Declare Function SafeArrayGetDim Lib "oleaut32.dll" (psa() As Any) As Long
Public Sub Main()
Dim MyArray() As String
Debug.Print SafeArrayGetDim(MyArray) ' zero
ReDim MyArray(64)
Debug.Print SafeArrayGetDim(MyArray) ' non-zero
Erase MyArray
Debug.Print SafeArrayGetDim(MyArray) ' zero
ReDim MyArray(31, 15, 63)
Debug.Print SafeArrayGetDim(MyArray) ' non-zero
Erase MyArray
Debug.Print SafeArrayGetDim(MyArray) ' zero
ReDim MyArray(127)
Debug.Print SafeArrayGetDim(MyArray) ' non-zero
Dim vArray As Variant
vArray = MyArray
' If you uncomment the next line, the program won't compile or run.
'Debug.Print SafeArrayGetDim(vArray) ' <- Type mismatch
End Sub
If the array is a string array, you can use the Join() method as a test:
Private Sub Test()
Dim ArrayToTest() As String
MsgBox StringArrayCheck(ArrayToTest) ' returns "false"
ReDim ArrayToTest(1 To 10)
MsgBox StringArrayCheck(ArrayToTest) ' returns "true"
ReDim ArrayToTest(0 To 0)
MsgBox StringArrayCheck(ArrayToTest) ' returns "false"
End Sub
Function StringArrayCheck(o As Variant) As Boolean
Dim x As String
x = Join(o)
StringArrayCheck = (Len(x) <> 0)
End Function
My only problem with API calls is moving from 32-bit to 64-bit OS's.
This works with Objects, Strings, etc...
Public Function ArrayIsInitialized(ByRef arr As Variant) As Boolean
On Error Resume Next
ArrayIsInitialized = False
If UBound(arr) >= 0 Then If Err.Number = 0 Then ArrayIsInitialized = True
End Function
If ChkArray(MyArray)=True then
....
End If
Public Function ChkArray(ByRef b) As Boolean
On Error goto 1
If UBound(b) > 0 Then ChkArray = True
End Function
You can solve the issue with Ubound() function, check if the array is empty by retrieving total elements count using JScript's VBArray() object (works with arrays of variant type, single or multidimensional):
Sub Test()
Dim a() As Variant
Dim b As Variant
Dim c As Long
' Uninitialized array of variant
' MsgBox UBound(a) ' gives 'Subscript out of range' error
MsgBox GetElementsCount(a) ' 0
' Variant containing an empty array
b = Array()
MsgBox GetElementsCount(b) ' 0
' Any other types, eg Long or not Variant type arrays
MsgBox GetElementsCount(c) ' -1
End Sub
Function GetElementsCount(aSample) As Long
Static oHtmlfile As Object ' instantiate once
If oHtmlfile Is Nothing Then
Set oHtmlfile = CreateObject("htmlfile")
oHtmlfile.parentWindow.execScript ("function arrlength(arr) {try {return (new VBArray(arr)).toArray().length} catch(e) {return -1}}"), "jscript"
End If
GetElementsCount = oHtmlfile.parentWindow.arrlength(aSample)
End Function
For me it takes about 0.4 mksec for each element + 100 msec initialization, being compiled with VB 6.0.9782, so the array of 10M elements takes about 4.1 sec. The same functionality could be implemented via ScriptControl ActiveX.
There are two slightly different scenarios to test:
The array is initialised (effectively it is not a null pointer)
The array is initialised and has at least one element
Case 2 is required for cases like Split(vbNullString, ",") which returns a String array with LBound=0 and UBound=-1.
Here are the simplest example code snippets I can produce for each test:
Public Function IsInitialised(arr() As String) As Boolean
On Error Resume Next
IsInitialised = UBound(arr) <> 0.5
End Function
Public Function IsInitialisedAndHasElements(arr() As String) As Boolean
On Error Resume Next
IsInitialisedAndHasElements = UBound(arr) >= LBound(arr)
End Function
Either of these two ways is valid to detect an uninitialized array, but they must include the parentheses:
(Not myArray) = -1
(Not Not myArray) = 0
' Function CountElements return counted elements of an array.
' Returns:
' [ -1]. If the argument is not an array.
' [ 0]. If the argument is a not initialized array.
' [Count of elements]. If the argument is an initialized array.
Private Function CountElements(ByRef vArray As Variant) As Integer
' Check whether the argument is an array.
If (VarType(vArray) And vbArray) <> vbArray Then
' Not an array. CountElements is set to -1.
Let CountElements = -1
Else
On Error Resume Next
' Calculate number of elements in array.
' Scenarios:
' - Array is initialized. CountElements is set to counted elements.
' - Array is NOT initialized. CountElements is never set and keeps its
' initial value of zero (since an error is
' raised).
Let CountElements = (UBound(vArray) - LBound(vArray)) + 1
End If
End Function
' Test of function CountElements.
Dim arrStr() As String
Dim arrV As Variant
Let iCount = CountElements(arrStr) ' arrStr is not initialized, returns 0.
ReDim arrStr(2)
Let iCount = CountElements(arrStr) ' arrStr is initialized, returns 3.
ReDim arrStr(5 To 8)
Let iCount = CountElements(arrStr) ' arrStr is initialized, returns 4.
Let arrV = arrStr
Let iCount = CountElements(arrV) ' arrV contains a boxed arrStr which is initialized, returns 4
Erase arrStr
Let iCount = CountElements(arrStr) ' arrStr size is erased, returns 0.
Let iCount = CountElements(Nothing) ' Nothing is not an array, returns -1.
Let iCount = CountElements(Null) ' Null is not an array, returns -1.
Let iCount = CountElements(5) ' Figure is not an array, returns -1.
Let iCount = CountElements("My imaginary array") ' Text is not an array, returns -1.
Let iCount = CountElements(Array(1, 2, 3, 4, 5)) ' Created array of Integer elements, returns 5.
Let iCount = CountElements(Array("A", "B", "C")) ' Created array of String elements, returns 3.
I see a lot of suggestions online about how to tell if an array has been initialized. Below is a function that will take any array, check what the ubound of that array is, redimension the array to ubound +1 (with or without PRESERVER) and then return what the current ubound of the array is, without errors.
Function ifuncRedimUbound(ByRef byrefArr, Optional bPreserve As Boolean)
On Error GoTo err:
1: Dim upp%: upp% = (UBound(byrefArr) + 1)
errContinue:
If bPreserve Then
ReDim Preserve byrefArr(upp%)
Else
ReDim byrefArr(upp%)
End If
ifuncRedimUbound = upp%
Exit Function
err:
If err.Number = 0 Then Resume Next
If err.Number = 9 Then ' subscript out of range (array has not been initialized yet)
If Erl = 1 Then
upp% = 0
GoTo errContinue:
End If
Else
ErrHandler.ReportError "modArray", ifuncRedimUbound, "1", err.Number, err.Description
End If
End Function
This worked for me, any bug in this?
If IsEmpty(a) Then
Exit Function
End If
MSDN
Dim someArray() as Integer
If someArray Is Nothing Then
Debug.print "this array is not initialised"
End If