How to Dynamically Filter Data to the Latest Waves

This article describes how to go from tables that show all data...

...to tables that only show data for the last 2 periods, for example:

Requirements

A data set that includes a Nominal (also known as categorical) wave variable. In this example, we have a variable called Wave that indicates which quarter the survey was completed in. Waves must be in ascending order when shown in a table, like:

Instructions for how to convert date/time variables to nominal variables can be found here: How to Create a Categorical Variable from a Date/Time Variable.

Method

1. In the Data Sources tree, hover over any variable and click Plus (+) > Custom Code > R > Numeric.

2. Paste the code below into the R Code editor:

unique.waves = levels(Wave) #Get wave categories
last.two.waves = unique.waves[(length(unique.waves)-1):length(unique.waves)] #Find last 2 waves
Wave %in% last.two.waves

The above code gets the levels or categories from the Wave variable. You will need to replace Wave with the Name of your nominal wave variable.
It then identifies the last 2 wave categories. Note, this code assumes the waves are in the correct order.
Finally, we return TRUE or FALSE based on whether the data matches these 2 wave categories.

3. Tick Usable as a filter.

4. Give the filter a Name and Label in the General tab of the object inspector .