sklein
asked on
Create empty VB integer array?
Split("") returns an "empty" string array (ubound = -1). Anyone noticed an equivalent function that returns an empty integer array? Alternatively, has anyone found a way to set an integer array to empty?
I'm trying to create a filter function that takes in a string array and returns an integer array, but since an empty string array is a valid input, I need to be able to create an equivalent empty integer array for return.
I'm trying to create a filter function that takes in a string array and returns an integer array, but since an empty string array is a valid input, I need to be able to create an equivalent empty integer array for return.
Two type errors - the last function should contain the code...
'Add a item
Filter = 1
ReDim IntegerArray(0) 'changed
IntegerArray(0) = 10 'changed
'Add a item
Filter = 1
ReDim IntegerArray(0) 'changed
IntegerArray(0) = 10 'changed
Another error ...
Function Filter(String, IntegerArray() As Integer)
'Start with no items
ReDim IntegerArray(0)
Filter = 0
'Add a item
ReDim IntegerArray(1)
IntegerArray(1) = 10
End Function
The first function shouldnt be a sub...:o)
Function Filter(String, IntegerArray() As Integer)
'Start with no items
ReDim IntegerArray(0)
Filter = 0
'Add a item
ReDim IntegerArray(1)
IntegerArray(1) = 10
End Function
The first function shouldnt be a sub...:o)
ASKER
Actually (as originally posted), I'm trying to produce a "filter function" that looks like the following:
Function CStrToInt(sArray() as String) as Integer()
In the case where sArray is empty (ubound(sArray) = -1), I want to return an Integer array which has the property that ubound() of it is also -1.
ubound(split("")) = -1, but split() returns a string array. I haven't been able to find an equivalent function that returns an "empty" integer array.
By the way, empty and uninitialized are different. ubound() of an uninitialized array generates an array bounds error.
Function CStrToInt(sArray() as String) as Integer()
In the case where sArray is empty (ubound(sArray) = -1), I want to return an Integer array which has the property that ubound() of it is also -1.
ubound(split("")) = -1, but split() returns a string array. I haven't been able to find an equivalent function that returns an "empty" integer array.
By the way, empty and uninitialized are different. ubound() of an uninitialized array generates an array bounds error.
Crazyman: actually it was supposed to be a sub to show that it did not need a return value, perhaps I should have said something about that. ;)
Sklein: The only way a function can return a array is (as far as I know) using a variant array. I believe using the approach with the result array as the second parameter is more efficient than using variants (variants are slow). Variant arrays are also used with the VB6 Split() function, if this is what you are trying to copy. Anyway, here's if you really want to use a variant array...
Function Split() As Variant
Dim SplitTemp As Variant
ReDim SplitTemp(1)
SplitTemp(0) = 1
SplitTemp(1) = 23
Split = SplitTemp
'If you want to try returning a 'empty result' uncomment
'the next line below this one
'Split = Null
End Function
The ReDim statement can not be used directly on the function variable, this is why I added the SplitTemp variable here. To try out the function you can use code like this (see the difference when you uncomment the "Split = Null" line and when it's commented)...
Dim Res As Variant
Res = Split()
If IsNull(Res) Then
Me.Caption = "Empty result"
Else
Me.Caption = UBound(Res)
End If
Sklein: The only way a function can return a array is (as far as I know) using a variant array. I believe using the approach with the result array as the second parameter is more efficient than using variants (variants are slow). Variant arrays are also used with the VB6 Split() function, if this is what you are trying to copy. Anyway, here's if you really want to use a variant array...
Function Split() As Variant
Dim SplitTemp As Variant
ReDim SplitTemp(1)
SplitTemp(0) = 1
SplitTemp(1) = 23
Split = SplitTemp
'If you want to try returning a 'empty result' uncomment
'the next line below this one
'Split = Null
End Function
The ReDim statement can not be used directly on the function variable, this is why I added the SplitTemp variable here. To try out the function you can use code like this (see the difference when you uncomment the "Split = Null" line and when it's commented)...
Dim Res As Variant
Res = Split()
If IsNull(Res) Then
Me.Caption = "Empty result"
Else
Me.Caption = UBound(Res)
End If
Lol
i was just being picky because it was a sub but had
end function
at the end...
i was just being picky because it was a sub but had
end function
at the end...
ASKER
Actually (as originally posted), I'm trying to produce a "filter function" that looks like the following:
Function CStrToInt(sArray() as String) as Integer()
In the case where sArray is empty (ubound(sArray) = -1), I want to return an Integer array which has the property that ubound() of it is also -1.
ubound(split("")) = -1, but split() returns a string array. I haven't been able to find an equivalent function that returns an "empty" integer array.
By the way, empty and uninitialized are different. ubound() of an uninitialized array generates an array bounds error.
Function CStrToInt(sArray() as String) as Integer()
In the case where sArray is empty (ubound(sArray) = -1), I want to return an Integer array which has the property that ubound() of it is also -1.
ubound(split("")) = -1, but split() returns a string array. I haven't been able to find an equivalent function that returns an "empty" integer array.
By the way, empty and uninitialized are different. ubound() of an uninitialized array generates an array bounds error.
ASKER
Unfortunately, using variant arrays as the result type doesn't work, as you can't assign a variant array to anything but another variant array. Thus, this model doesn't work for doing (say) type conversion.
If worse comes to worse, I'll do something like:
Function CStrToInt(saInput() as String, iaResult() as Integer) as Integer
where the function result contains the number of elements in the result array.
That way, for the case where the input array is empty, I can leave iaResult uninitialized and return a value of zero for the function.
But still, what I REALLY want is to figure out how to produce an integer array whose ubound() is -1. I suppose it should be feasible to write a C++ function that creates such an array. Or perhaps use LSet between two UDTs...
If worse comes to worse, I'll do something like:
Function CStrToInt(saInput() as String, iaResult() as Integer) as Integer
where the function result contains the number of elements in the result array.
That way, for the case where the input array is empty, I can leave iaResult uninitialized and return a value of zero for the function.
But still, what I REALLY want is to figure out how to produce an integer array whose ubound() is -1. I suppose it should be feasible to write a C++ function that creates such an array. Or perhaps use LSet between two UDTs...
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ASKER
Unfortunately, using variant arrays as the result type doesn't work, as you can't assign a variant array to anything but another variant array. Thus, this model doesn't work for doing (say) type conversion.
If worse comes to worse, I'll do something like:
Function CStrToInt(saInput() as String, iaResult() as Integer) as Integer
where the function result contains the number of elements in the result array.
That way, for the case where the input array is empty, I can leave iaResult uninitialized and return a value of zero for the function.
But still, what I REALLY want is to figure out how to produce an integer array whose ubound() is -1. I suppose it should be feasible to write a C++ function that creates such an array. Or perhaps use LSet between two UDTs...
If worse comes to worse, I'll do something like:
Function CStrToInt(saInput() as String, iaResult() as Integer) as Integer
where the function result contains the number of elements in the result array.
That way, for the case where the input array is empty, I can leave iaResult uninitialized and return a value of zero for the function.
But still, what I REALLY want is to figure out how to produce an integer array whose ubound() is -1. I suppose it should be feasible to write a C++ function that creates such an array. Or perhaps use LSet between two UDTs...
ASKER
Vbmaster--
I'll have to say I didn't think of that. It's not exactly the same, as I can access the -1'th element of the array (whereas I can't access the -1'th element of the value returned by split("")), but it's good enough for my purposes... Thanks.
I'll have to say I didn't think of that. It's not exactly the same, as I can access the -1'th element of the array (whereas I can't access the -1'th element of the value returned by split("")), but it's good enough for my purposes... Thanks.
Sub Filter(String, IntegerArray() As Integer)
'Start with no items
ReDim IntegerArray(0)
Filter = 0
'Add a item
ReDim IntegerArray(1)
IntegerArray(1) = 10
End Function
Dim a As Integer
Dim sValue As String
Dim IntegerArray() As Integer
Call Filter(sValue, IntegerArray())
If (UBound(IntegerArray) = 0) Then
'No items was saved into the array
Else
'Do something with the saved item (from 1..Ubound(IntegerArray))
For a = 1 to Ubound(IntegerArray)
Next
End If
You can also use a function to return the number of items saved into the array. The advantage of this method is that it is more efficient than the first one, this new method uses all items.
Function Filter(String, IntegerArray() As Integer) As Integer
'Start with no items
Erase IntegerArray 'this line will clear the array
Filter = 0
'Add a item
Filter = 1
ReDim IntegerArray(1)
IntegerArray(1) = 10
End Function
Dim a As Integer
Dim sValue As String
Dim IntegerArray() As Integer
Dim Count as Integer
Count = Filter(sValue, IntegerArray())
If (Count = 0) Then
'No items was saved into the array
Else
'Do something with the saved item (from 0..Count-1)
For a = 0 To (Count-1)
Next
End If