vba Excel 2010: convert string array into int array

Question

Dim myarray(2) as Variant

myarray(0)=\"3\"
myarray(1)=\"4\"
myarray(2)=\"5\"
myarray(3)=\"9\"

I want it to become

myarray(0)=3
my         


        

Answer 1

Looping through the array and converting the values one-by-one is fast enough. Here's a snippet of code to show how fast a conversion loop is relative to performing your cell I/O:

Private Const I_MAX = 10000
Private Const J_MAX = 200
Private Declare Function GetTickCount Lib "kernel32.dll" () As Long

Sub ticktest()
    Dim ticks As Long, i As Long, j As Long
    Dim v() As Variant
    Dim a() As Long 'VBA integers are internally stored as longs
    Dim r As Range

    Set r = [A1].Resize(I_MAX, J_MAX)
    ReDim a(1 To I_MAX, 1 To J_MAX)

    ticks = GetTickCount
    v = r
    Debug.Print "Read from range: " & GetTickCount - ticks

    Debug.Print "Type of values in v(): " & TypeName(v(1, 1))

    ticks = GetTickCount
    For i = 1 To I_MAX
        For j = 1 To J_MAX
            a(i, j) = v(i, j)
        Next j
    Next i
    Debug.Print "Copy with cast to Long: " & GetTickCount - ticks

    ticks = GetTickCount
    For i = 1 To I_MAX
        For j = 1 To J_MAX
            v(i, j) = CLng(v(i, j))
        Next j
    Next i
    Debug.Print "In-place cast to Variant/Long: " & GetTickCount - ticks

    ticks = GetTickCount
    r = a
    Debug.Print "Write from long array: " & GetTickCount - ticks

    ticks = GetTickCount
    r = v
    Debug.Print "Write from variant array: " & GetTickCount - ticks

    For i = 1 To I_MAX
        For j = 1 To J_MAX
            v(i, j) = CStr(v(i, j))
        Next j
    Next i
    r = v
End Sub

With these values for I_MAX and J_MAX we get a 2,000,000–entry array, where reading from and writing to the worksheet is about 4x slower than converting each entry from a Variant/String to a Long:

Read from range: 749
Type of values in v(): String
Copy with cast to Long: 546
In-place cast to Variant/Long: 842
Write from long array: 921
Write from variant array: 1248

Read from range: 749
Type of values in v(): String
Copy with cast to Long: 546
In-place cast to Variant/Long: 827
Write from long array: 905
Write from variant array: 1248

Read from range: 749
Type of values in v(): String
Copy with cast to Long: 531
In-place cast to Variant/Long: 826
Write from long array: 905
Write from variant array: 1279

So there's no real need to avoid loops, with one caveat: If you do the cell I/O in a loop, performance becomes abysmal. Here, for example, a loop of r(i, j) = v(i, j) takes a full 100 seconds (that's 100,000 ticks, or 2,000x the conversion loop time) to complete.