I have an Excel spreadsheed like the one shown below

```
A B
10.02.2007 10
10.03.2007 12
```

Column A is date and B is price of share

Now my task is calculate financial return of share using formula

```
return = ln(price_today / price_yesterday)
```

Now in another sreadsheet I need to create a new column called Return

In this column i need to place formula like `= ln(B2/B1)`

but on condition that this formula is only applied date in column A is in range

`StartDate < currentDate < EndDate`

.

So I want to

- apply my formula only to specific period say only to 2007 year
- have new column placed in another spreadsheet starting from given location say A1

Please suggest

To reference a cell in another workbook you need to use something like

```
[Book1.xlsx]Sheet1!$A$1
```

To find the year number you need to ensure that the column is a valid Date column, and use something like

```
=IF(YEAR([Book1.xlsx]Sheet1!$A$1) = 2007,LN([Book1.xlsx]Sheet1!$B$2/[Book1.xlsx]Sheet1!$B$1), 0)
```

And also maybe Excel: And Function to allow for the `StartDate < currentDate < EndDate`

Tags: excelexcel, sed