autofill with adjacent cell reference

[RAexcel]

I have a large set of data in column B with multiple duplicates and I am in the middle of entering data into column A.

I would like to find a way that once I enter the data into column A all other "A" fields adjacent to the same B fields will auto populate.

I do not have a data set to reference for column A as I am finding the data in another software and cannot export it to excel.


Example:
Colum A Column B

ABC	123858
	555658
	123585

I would like that column A3 auto fill to abc because B1 and B3 are the exact same.

[sktneer]

May be this......

In A3

=IFERROR(INDEX(A$1:A2,MATCH(B3,B$1:B2,0)),"")

[ChemistB]

This would require VBA.
Right click on the sheet tab and "View Code" Then paste this in (assumes you are typing into Column A and looking in B for matches)

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
If Intersect(Target, Range("A:A")) Is Nothing Then Exit Sub
Beginrow = Target.Row
Lstrow = Cells(Rows.Count, "B").End(xlUp).Row
chkval = Target.Offset(0, 1).Value

For i = Beginrow To Lstrow
    If Target.Offset(i, 1).Value = chkval Then
        Target.Offset(i, 0) = Target.Value
    End If
Next i

End Sub

[RAexcel]

Thanks ChemistB that works perfectly! Saving me hours of data entry..

Thanks again

RA

[ChemistB]

Glad to help