# Reducing an array

I have an array of data read off a worksheet using the statement

maxrds = dta.Range("a" & xls.Application.Rows.Count).End(xlUp).Row - datstart + 1

All variables are variants.

How can I create a similar array which has only even numbers in the first column?

Saqib
LVL 43
###### Who is Participating?

Commented:

Saqib,

This code uses a Mod test to dump only the even numbers to the second array

A Redim Preserve is used to trim the second array to the correct size

For future reference my array article is at  http://www.experts-exchange.com/A_2684.html

Cheers

Dave
``````Sub Recut()
Dim X
Dim Y
Dim lngRow As Long
Dim lngRow2 As Long
X = Application.Transpose(Range([a5], Cells(Rows.Count, "A").End(xlUp)))
Y = X
For lngRow = 1 To UBound(X)
If X(lngRow) Mod 2 = 0 Then
lngRow2 = lngRow2 + 1
Y(lngRow2) = X(lngRow)
End If
Next
ReDim Preserve Y(lngRow2)
End Sub
``````
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Commented:
Saqib,

I think you will need to create a second array reading in every second record from your initial array (faster than writing every second cell to a single array)

Cheers

Dave
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EngineerAuthor Commented:
Hi, Dave,

I have not declared the size of the original array. It sizes it based on the assignment statement above. I would like to know a way to assign this to the new array without defining the length. So the main list might have 100 entries and the new list might have 70

The numbers would have to be checked for evenness, they are not regularly incrementing.
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EngineerAuthor Commented:
Sorry I had given the wrong assignment statement in the question. That was for calculation the number of entries in the range. The range assignment is given here

rds = WorksheetFunction.Transpose(dta.Range(dta.Cells(datstart, 1), dta.Cells(maxrds + datstart - 1, 1)).Value)

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Commented:
Can you pls post a sample Saqib
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EngineerAuthor Commented:
Dave,

I have created this file with the given numbers in column A.

In column D I have shown what values I would like to see in the reduced array. This column is not normally present.

I have also created a macro which assigns column A values to rds and column D values to rds2.

I would like to have rds contain the contents of rds2 instead of having a new variable rds2.

Saqib
Reducearray.xls
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