Excel's Formula - sisman

Chapter 17: Charting Techniques 447
Cell A1 contains the value 10. The value in this cell determines which rows to hide. Column B contains
identical formulas that use the value in cell A1. For example, the formula in cell B4 is as follows:
=MOD(ROW()–ROW($A$4),$A$1)
This formula subtracts the current row number from the first data row number in the table, and
uses the MOD function to calculate the remainder when that value is divided by the value in A1.
As a result, every nth cell (beginning with row 4) contains 0. Use the filter drop-down list in cell
B3 to specify a filter that shows only the rows that contain a 0 in column B.
If you change the value in cell A1, you need to respecify the filter criteria for column B.
(The rows will not hide automatically.)
Although this example uses a table (created using Insert➜Tables➜Table), the technique also
works with a normal range of data as long as it has column headers. Choose Data➜Sort &
Filter➜Filter to enable filtering.
Plotting the last n data points
You can use a technique that makes your chart show only the most recent data points in a column.
For example, you can create a chart that always displays the most recent six months of
data (see Figure 17-11).
The instructions that follow describe how to create the chart in this figure:
1. Create a worksheet like the one shown in Figure 17-11, and create a chart that uses the
data in A1: B26.
2. Choose Formulas➜Defined Names➜Name Manager to bring up the Name Manager dialog
box.
3. Click New to display the New Name dialog box.
4. In the Name field, type MonthRange. In the Refers To field, enter this formula:
=OFFSET(Sheet1!$A$1,COUNTA(Sheet1!$A:$A)–6,0,6,1)
Notice that the OFFSET function refers to cell A1 (not the cell with the first month).
5. Click OK to close the New Name dialog box.
6. Click New to define the second name.
7. In the New Name dialog box, type SalesRange in the Names in Workbook field. Enter this
formula in the Refers To field:
=OFFSET(Sheet1!$B$1,COUNTA(Sheet1!$B:$B)–6,0,6,1)
8. Click OK, and then click Close to close the Name Manager dialog box.