Ranges

Unlike many of our programming concepts, the idea of a Range is particular to Excel The ideas and code discussed in these slides can be found in demo ForEachForNext We show how to use a For Each loop with a Range, and contrast with a For variable nested loop that will help prepare us to deal with arrays

A Range is a Collection of Cells VBA in Excel has a data type Range A Range can be a single cell, a block of cells, or a group of blocks of cells (we’ll stick with the first two possibilities) You declare a Range variable in the usual way: Dim workArea As Range Dim aCell As Range

Using For Each with a Range The For Each type of loop is designed to be used when you want to do the same thing to every item in a collection A Range is a collection of cells This loop clears all the cells in global range workArea: Sub ClearCells() Dim aCell As Range For Each aCell In workArea aCell.Value = Empty Next aCell End Sub

Put a 1 in Each Cell in a Range Sub ForEachDemo() Dim aCell As Range For Each aCell In workArea aCell.Value = 1 Next aCell End Sub

Treat Cells Differently If you don’t want to do the same exact thing with each cell, then you need a different kind of loop For loops using variables work very well in this case For a range that is just a single row or column, one loop is fine. For a two-dimensional range, you need nested loops

One-Dimensional Example (row) To set elements 1 to size of the first row to two times their column index: For colNdx = 1 To size Cells(1, colNdx) = 2 * colNdx Next colNdx

Two-Dimensional Example Sub ForVariableDemo() Dim rowNdx, colNdx As Long For rowNdx = 1 To size For colNdx = 1 To size Cells(rowNdx, colNdx).Value = rowNdx + colNdx Next colNdx Next rowNdx End Sub

These are Simple Examples You could use a much more complex formula instead of the simple ones we used in these examples For example, you could compute an amortization table or a projection of building an interest-bearing account under different scenarios you might program