autonumber  - script function
                This script function returns a unique integer value for each distinct evaluated value of expression encountered during the script execution. This function can be used e.g. for creating a compact memory representation of a complex key.
Syntax:
autonumber(expression[ , AutoID])
Arguments:
| Argument | Description | 
|---|---|
| AutoID | 
                                 In order to create multiple counter instances if the autonumber function is used on different keys within the script, the optional parameter AutoID can be used for naming each counter.  | 
                        
Example: Creating a composite key
In this example we create a composite key using the autonumber function to conserve memory. The example is brief for demonstration purpose, but would be meaningful with a table containing a large number of rows.
| Region | Year | Month | Sales | 
|---|---|---|---|
| North | 2014 | May | 245 | 
| North | 2014 | May | 347 | 
| North | 2014 | June | 127 | 
| South | 2014 | June | 645 | 
| South | 2013 | May | 367 | 
| South | 2013 | May | 221 | 
The source data is loaded using inline data. Then we add a preceding load which creates a composite key from the Region, Year and Month fields.
The resulting table looks like this:
| Region | Year | Month | Sales | RYMkey | 
|---|---|---|---|---|
| North | 2014 | May | 245 | 1 | 
| North | 2014 | May | 347 | 1 | 
| North | 2014 | June | 127 | 2 | 
| South | 2014 | June | 645 | 3 | 
| South | 2013 | May | 367 | 4 | 
| South | 2013 | May | 221 | 4 | 
In this example you can refer to the RYMkey, for example 1, instead of the string 'North2014May' if you need to link to another table.
Now we load a source table of costs in a similar way. The Region, Year and Month fields are excluded in the preceding load to avoid creating a synthetic key, we are already creating a composite key with the autonumber function, linking the tables.
Now we can add a table chart to a sheet, and add the Region, Year and Month fields, as well as Sum measures for the sales and the costs. the table will look like this:
| Region | Year | Month | Sum([Sales]) | Sum([Costs]) | 
|---|---|---|---|---|
| Totals | - | - | 1952 | 784 | 
| North | 2014 | June | 127 | 199 | 
| North | 2014 | May | 592 | 56 | 
| South | 2014 | June | 645 | 64 | 
| South | 2013 | May | 588 | 465 |