Array as Item in Dictionary: How set value to array index?-CodePudding

I have dictionary. Dictionary have array of 8 elements. Can I set new value of existing array in dictionary? My code below:

Option Explicit
Sub test()
    Dim dict As Dictionary
    Dim arr() As Long
    Dim i As Variant
    Set dict = New Dictionary
    ReDim arr(1 To 8)
    dict.Add "L", arr()
    dict.Item("L")(3) = 500
    For Each i In dict.Item("L")
        Debug.Print (i)
    Next
End Sub

Line dict.Item("L")(3) = 500 staying array element empty. What I am doing wrong?

Or there is only one true way?

arr(3) = 500
dict.Item("L") = arr

CodePudding user response：

I made it. Trick in user function. Now it's work fine for me. All previous data are preserved without copying

Sub test()
    Dim dict As New Scripting.Dictionary
    Dim i As Integer, index As Integer
    Dim newVal As Long
    ReDim arr(1 To 8) As Long
    arr(1) = 200
    dict.Add "L", arr
    index = 3
    newVal = 500
    dict("L") = updateItem(dict("L"), index, newVal)
    For i = LBound(dict("L")) To UBound(dict("L"))
        MsgBox dict("L")(i)
    Next
End Sub

Function updateItem(ByRef currentItem As Variant, ByRef index As Integer, ByRef newVal As Long)
    currentItem(index) = newVal
    updateItem = currentItem
End Function

CodePudding user response：

I ran into this issue once.

You can't change a single value in an array of a dictionary, you have to change the whole array

so this should work

Sub test()
    Dim dict As Dictionary
    Dim arr() As Long
    Dim i As Variant
    Set dict = New Dictionary
    ReDim arr(1 To 8)
    arr(3) = 500
    dict.Add "L", arr()
    For Each i In dict.item("L")
        Debug.Print (i)
    Next
End Sub

but what if you want to change a value in an already populated array in a dictionary?

simple

define a new array to hold the values in the dictionary array
Make the changes you want
Load the new array into the dictionary using the .item property (Ex: dict.item("L") = NewArr() )

Sub test()
    Dim dict As Dictionary
    Dim arr() As Long
    Dim i As Variant
    Dim newarr() As Long
    
    Set dict = New Dictionary
    ReDim arr(1 To 8)
    ReDim newarr(1 To 8)
    arr(3) = 500
    dict.Add "L", arr()
    newarr = dict("L")
    newarr(3) = 1000
    dict.item("L") = newarr()
    
    For Each i In dict.item("L")
        Debug.Print (i)
    Next
End Sub