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As you get more into Excel’s statistical features, you work increasingly with formulas that have multiple arguments. Oftentimes, these arguments refer to arrays of cells, as in the examples I describe earlier in this chapter.

If you attach meaningful names to these arrays, it helps you keep straight what you’re doing. Also, if you return to a worksheet after not working on it for a while, meaningful array names can help you quickly get back into the swing of things. Another benefit: If you have to explain your worksheet and its formulas to others, meaningful array names are tremendously helpful.

Excel gives you an easy way to attach a name to a group of cells (but not on the iPad). In Figure 2-12, column C is named Revenue_Millions, indicating “revenue in millions of dollars.” As it stands, that just makes it a bit easier to read the column. If I explicitly tell Excel to treat Revenue_Millions as the name of the array of cells C2 through C13, however, I can use Revenue_Millions whenever I refer to that array of cells.

FIGURE 2-12: Defining names for arrays of cells.

Why did I use Revenue_Millions and not Revenue (Millions) or Revenue In Millions or Revenue: Millions? Because Excel doesn’t like blank spaces or symbols in its names — that’s why. In fact, here are four rules to follow when you supply a name for a range of cells. The name

 Must begin with an alphabetic character — a letter rather than a number or a punctuation mark.

 Must be unique within the workbook.

 Cannot contain spaces or symbols (as I just mentioned) — use an underscore to denote a space between words in the name.

 Cannot duplicate any cell reference in the worksheet.

Otherwise, Excel gives you up to 255 characters to get creative with the name.

Here’s how to define a name:

1 Add a descriptive name at the top of a column (or to the left of a row) you want to name.(Refer to Figure 2-10.)

2 Select the range of cells you want to name.In this example, that’s cells C2 through C13. Why not include C1? I explain in a second.

3 Right-click the selected range.This step opens the pop-up menu shown in Figure 2-13.FIGURE 2-13: Right-clicking a selected cell range opens this pop-up menu.

4 From this pop-up menu, choose Define Name.This selection opens the New Name dialog box. (See Figure 2-14.) As you can see, Excel knows that Revenue_Millions is the name of the array and that Revenue_Millions refers to cells C2 through C13. When presented with a selected range of cells to name, Excel looks for a nearby name — just above a column or just to the left of a row. If no name is present, you get to supply one in the New Name dialog box. (You can also open the New Name dialog box by choosing Formulas | Define Name.)FIGURE 2-14: The New Name dialog box. When you select a range of cells, like a column, with a name at the top, you can include the cell with the name in it and Excel attaches the name to the range. I strongly advise against doing this, however. Why? If I select C1 through C13, the name Revenue_Millions refers to cells C1 through C13, not C2 through C13. In that case, the first value in the range is text, and the others are numbers.For a formula such as SUM (or SUMIF or SUMIFS, which I discuss next), this doesn't make a difference: In those formulas, Excel just ignores values that aren’t numbers. If you have to use the whole array in a calculation, however, it makes a huge difference: Excel thinks the name is part of the array and tries to use it in the calculation. You see this in the next section, on creating your own array formulas.

5 Click OK.Excel attaches the name to the range of cells.

Now I have the convenience of using the name in a formula. Here, selecting a cell (like C14) and entering the SUM formula directly into C14 opens the boxes shown in Figure 2-15.

As the figure shows, the boxes open as you type. Selecting Revenue_Millions and pressing the Tab key fills in the formula in a way that Excel understands. You have to supply only the close parenthesis (see Figure 2-16) and press Enter in order to see the result.

Using the named array, then, the formula is

=SUM(Revenue_Millions)

which is more descriptive than

=SUM(C2:C13)

FIGURE 2-15: Entering a formula directly into a cell opens these boxes.

FIGURE 2-16: Completing the formula.

A couple of other formulas show just how convenient this naming capability can be. These formulas, SUMIF and SUMIFS, add a set of numbers if specific conditions in one cell range (SUMIF) or in more than one cell range (SUMIFS) are met.

To take full advantage of naming, I name my table's column A (Year) and column B (Region) in the same way I named column C.

When you define a name for a cell range like B2:B13 in this example, beware: Excel can be quirky when the cells hold names. It might guess that the name in the uppermost cell is the name you want to assign to the cell range. In this case, Excel guesses North for the name rather than Region. If that happens, you make the change in the New Name dialog box.

To keep track of the names in a worksheet, choose Formulas | Name Manager from the main menu to open the Name Manager box, shown in Figure 2-17. (The nearby buttons in the Defined Names area of the Ribbon — Define Name, Use in Formula, and Create from Selection — come in handy, so keep them in mind for the future.)

FIGURE 2-17: Managing the Defined Names in a worksheet.

Next, I sum the data in column C, but only for the North region. That is, I consider a cell in column C only if the corresponding cell in column B contains North. To do this, I follow these steps:

1 Select a cell for the formula result.My selection here is C15.

2 Choose Formulas | Math & Trig.

3 From the pop-up menu that appears, choose SUMIF.This selection opens the Function Arguments dialog box, shown in Figure 2-18.SUMIF has three arguments. The first, Range, is the range of cells to evaluate for the condition to include in the sum (North, South, East, or West, in this example). The second, Criteria, is the specific value in the range (North, for this example). The third, Sum:range, holds the values I sum.FIGURE 2-18: The Function Arguments dialog box for SUMIF.

4 In the Function Arguments dialog box, enter the appropriate values for the arguments.Here's where another Defined Names button comes in handy. In that Ribbon area, click the down arrow next to Use in Formula to open the drop-down list shown in Figure 2-19.Choosing from this list fills in the Function Arguments dialog box, as shown in Figure 2-20. I had to type North into the Criteria box. Excel adds the double quotes.

5 Click OK.The result appears in the selected cell. In this example, it’s 78.

FIGURE 2-19: The Use in Formula drop-down list.

In the Formula bar, this line appears:

=SUMIF(Region,"North", Revenue_Millions)

If you choose to, you can type the line exactly that way into the Formula bar, without using the dialog box or the drop-down list. When you don't use the dialog box, you have to supply the double quotes around the criteria.

FIGURE 2-20: Completing the Function Arguments dialog box for SUMIF.

The formula in the Formula bar is easier to understand than

= SUMIF(B2:B13,"North", C2:C13)

isn’t it?

Incidentally, the same cell range can be both the Range and the Sum:range. For example, to sum just the cells for which Revenue_Millions is less than 25, you’d use

=SUMIF(Revenue_Millions, "< 25", Revenue_Millions)

The second argument (Criteria) is always in double quotes.

What about SUMIFS? That one is useful if you want to find the sum of revenues for North but only for the years 2006 and 2007. Follow these steps to use SUMIFS to find this sum:

1 Select a cell for the formula result.The selected cell is C17.

2 Choose Formulas | Math & Trig.

3 From the pop-up menu that appears, choose SUMIFS.This step opens the Function Arguments dialog box.

4 In the Function Arguments dialog box, enter the appropriate values for the arguments, as shown in Figure 2-21.Notice that, in SUMIFS, the Sum Range argument appears first. In SUMIF, however, it appears last.Note that the formula in the Formula bar is now=SUMIFS(Revenue_Millions,Year,"<2008",Region,"North")FIGURE 2-21: The completed Function Arguments dialog box for SUMIFS.

5 Click OK.The answer, 46, appears in the selected cell.

With unnamed arrays, the formula would have been

=SUMIFS(C2:C13,A2:A13,"<2008",B2:B13,"North")

which seems much harder to comprehend.

A defined name involves absolute referencing. (See Chapter 1.) Therefore, if you try to autofill from a named array, you'll be in for an unpleasant surprise: Rather than autofill a group of cells, you copy a value over and over again.

Here’s what I mean. Suppose you assign the name Series_1 to A2:A11 and Series_2 to B2:B11. In A12, you calculate SUM(Series_1). Because you’re clever, you figure you’ll just drag the result from A12 to B12 to calculate SUM(Series_2). What do you find in B12? SUM(Series_1) — that's what.

Excel does not treat array names as case-sensitive. If the named array is Test, for example, SUM(Test), SUM(test), and SUM(tEST) all give you the same result.

You can't name an array in Excel on the iPad. If you name an array in a Windows or Mac Excel spreadsheet, however, and your Microsoft 365 account includes the iPad, you can open that spreadsheet on the iPad and the named array works just fine.