You can use expressions to create calculated dimensions. A calculated dimension consists of an expression involving one or more fields. All standard functions may be used.
There are cases when calculated dimensions are powerful in data analysis, for example, if you want to generate the dimensions values during analysis, when dimension values are dependent on the selections.
Calculated dimensions are also useful if you want to modify a field.
Once you have created a calculated dimension, you can use it as any other dimension.
You have a field called Calendar Month that includes each of the months of the year. In your app, you want include a table that shows the sales for each of the first 6 months of the year. For the rest of the months, you want to see a total. You can use an expression to create this calculated dimension.
If ([Calendar Month] <7, [Calendar Month], 'Rest')