Page 365 - Excel 2007 Bible

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Part II
Working with Formulas and Functions
If you accidentally press Ctrl+Enter (instead of Ctrl+Shift+Enter) after editing an array
CAUTION
CAUTION
formula, the formula will be entered into each selected cell, but it will no longer be an
array formula. And it will probably return an incorrect result. Just reselect the cells, press F2, and then
press Ctrl+Shift+Enter.
Although you can’t change any individual cell that makes up a multicell array formula, you can apply for-
matting to the entire array or to only parts of it.
Expanding or contracting a multicell array formula
Often, you may need to expand a multicell array formula (to include more cells) or contract it (to include
fewer cells). Doing so requires a few steps:
1. Select the entire range that contains the array formula.
2. Press F2 to enter Edit mode.
3. Press Ctrl+Enter. This step enters an identical (non-array) formula into each selected cell.
4. Change your range selection to include additional or fewer cells.
5. Press F2 to re-enter Edit mode.
6. Press Ctrl+Shift+Enter.
Array Formulas: The Downside
f you’ve followed along in this chapter, you probably understand some of the advantages of using array for-
Imulas. The main advantage, of course, is that an array formula enables you to perform otherwise impossible
calculations. As you gain more experience with arrays, however, you undoubtedly will also discover some
disadvantages.
Array formulas are one of the least understood features of Excel. Consequently, if you plan to share a work-
book with someone who may need to make modifications, you should probably avoid using array formulas.
Encountering an array formula when you don’t know what it is can be very confusing.
You might also discover that you can easily forget to enter an array formula by pressing Ctrl+Shift+Enter. (And
don’t forget: If you edit an existing array, you must remember to use this key combination to complete the
edits.) Except for logical errors, this is probably the most common problem that users have with array formu-
las. If you press Enter by mistake after editing an array formula, just press F2 to get back into Edit mode and
then press Ctrl+Shift+Enter.
Another potential problem with array formulas is that they can slow your worksheet’s recalculations, espe-
cially if you use very large arrays. On a faster system, this delay in speed may not be a problem. But, con-
versely, using an array formula is almost always faster than using a custom VBA function. See Chapter 40 for
more information about creating custom VBA functions.

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