# array algorithm

Hi,

Please kindly assist how can we do something like this:

arr_req=1,2,3,4

desired output:
arr_req=1,1,2,2,3,3,4,4

Thanks.

For i = 0 To UBound(Arr_Req)
ReDim Preserve Arr_Req(UBound(Arr_Req) + 1)
For x = UBound(Arr_Req) To (i + 1) Step -1
Arr_Req(x) = Arr_Req(x - 1)
Next x

If i = 0 Then
Arr_Req(i + 1) = Arr_Req(i)
ElseIf i Mod 2 = 0 Then
Arr_Req(i + 1) = Arr_Req(i + 2)
End If
Debug.Print Join(Arr_Req, ",")
Next i
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Billing EngineerCommented:
redim preserve arr_req ( lbound(arr_req) to (2*(ubound(arr_req)+1)  - 1  ) as x

for i = ubound ( arr_req ) to lbound(arr_req) + 1 step -1
arr_req ( i ) = arr_req ( i / 2  - i % 2 )
next
0
Author Commented:
Error returned: user undefined: pointing to line 1

ReDim Preserve Arr_Req(LBound(Arr_Req) To (2 * (UBound(Arr_Req) + 1) - 1)) As x   <line 1
For i = UBound(Arr_Req) To LBound(Arr_Req) + 1 Step -1
Arr_Req(i) = Arr_Req(i / 2 - i Mod 2)
Next
Debug.Print Join(Arr_Req, ",")
0
Author Commented:
by the way, does the code also works on other values?

i.e.
arr_req=41,22,33,54,1,2,3,7,8

desired output:
arr_req=41,41,22,22,33,33,54,54,1,1,2,2,3,3,7,7,8,8
0
Billing EngineerCommented:
replace the as x obviously with as integer or as string.

>by the way, does the code also works on other values?
there is no limitation in the data, only the array size is limited (to 64 K)
0
Author Commented:
Glad to know that it is unlimited, not sure what I have missed the result out put came out:

1,1,2,1,3,3,4,3

Debug.Print "--------------original----------"
Debug.Print Join(Arr_Req, ",")

ReDim Preserve Arr_Req(LBound(Arr_Req) To (2 * (UBound(Arr_Req) + 1) - 1)) As String
For i = UBound(Arr_Req) To LBound(Arr_Req) + 1 Step -1
Arr_Req(i) = Arr_Req(i / 2 - i Mod 2)
Debug.Print Join(Arr_Req, ",")
Next

Debug.Print "--------------new--------------"
Debug.Print UBound(Arr_Req)
Debug.Print Join(Arr_Req, ",")
Exit Sub

--------------original----------
1,2,3,4
1,2,3,4,,,,3
1,2,3,4,,,4,3
1,2,3,4,,3,4,3
1,2,3,4,3,3,4,3
1,2,3,1,3,3,4,3
1,2,2,1,3,3,4,3
1,1,2,1,3,3,4,3
--------------new--------------
1,1,2,1,3,3,4,3
0
Commented:
try this:

Dim arr_req() As Integer
ReDim arr_req(4)
Dim i As Integer
arr_req(0) = 1
arr_req(1) = 2
arr_req(2) = 3
arr_req(3) = 4

ReDim Preserve arr_req(LBound(arr_req) To (2 * (UBound(arr_req)) - 1))
For i = UBound(arr_req) To LBound(arr_req) Step -1
arr_req(i) = arr_req(i \ 2)  ' uses INTEGER divide (\ not /)
Next

AW
0
Author Commented:
were almost there, sad to say, it missed the last array element "4"
result returned:

--------------original----------
1,2,3,4
1,2,3,4,,3
1,2,3,4,3,3
1,2,3,2,3,3
1,2,2,2,3,3
1,1,2,2,3,3
1,1,2,2,3,3
--------------new--------------
1,1,2,2,3,3
0
Billing EngineerCommented:

Dim arr_req() As Integer
ReDim arr_req(4)
Dim i As Integer
arr_req(0) = 1
arr_req(1) = 2
arr_req(2) = 3
arr_req(3) = 4

ReDim Preserve arr_req(LBound(arr_req) To (2 * (UBound(arr_req)+1) - 1))
For i = UBound(arr_req) To LBound(arr_req) Step -1
arr_req(i) = arr_req(i \ 2)  ' uses INTEGER divide (\ not /)
Next

AW
0

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Billing EngineerCommented:
wanted to say that there is only a minor correction to ArthurWoods code
0
Author Commented:
thanks so much angelIII and ArthurWoods!
0
Commented:
thanks angelIII.  Thought I had fully tested the code, but oh well.

AW
0
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