Microsoft Office

Introducing Array Formulas
One of Excel’s most interesting (and most powerful) features is its ability to
work with arrays in formulas. When you understand this concept, you’ll
be able to create elegant formulas that appear to perform spreadsheet
magic.
This chapter introduces the concept of arrays and is required reading for anyone
who wants to become a master of Excel formulas. Chapter 18 continues with lots
of useful examples.
Understanding Array Formulas
If you do any computer programming, you’ve probably been exposed to the concept
of an array. An array is simply a collection of items operated on collectively
or individually. In Excel, an array can be one dimensional or two dimensional.
These dimensions correspond to rows and columns. For example, a onedimensional
array can be stored in a range that consists of one row (a horizontal
array) or one column (a vertical array). A two-dimensional array can be stored in a
rectangular range of cells. Excel doesn’t support three-dimensional arrays (but its
VBA programming language does).
As you’ll see, arrays need not be stored in cells. You can also work with arrays
that exist only in Excel’s memory. You can then use an array formula to manipulate
this information and return a result. An array formula can occupy multiple
cells or reside in a single cell.
This section presents two array formula examples: an array formula that occupies
multiple cells and another array formula that occupies only one cell.
IN THIS CHAPTER
The definition of an array and an
array formula
One-dimensional versus twodimensional
arrays
How to work with array
constants
Techniques for working with
array formulas
Examples of multicell array
formulas
Examples of array formulas that
occupy a single cell
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