# Set modifiers with dollar-sign expansions

Variables and other dollar-sign expansions can be used in set expressions.

Examples:

Examples and results

| Example | Result |
| --- | --- |
| sum( {$<Year = {$(#vLastYear)}>} Sales ) | Returns the sales for the previous year in relation to current selection. Here, a variable vLastYear containing the relevant year is used in a dollar-sign expansion. |
| sum( {$<Year = {$(#=Only(Year)-1)}>} Sales ) | Returns the sales for the previous year in relation to current selection. Here, a dollar-sign expansion is used to calculate previous year. |