How to Create Dynamic Period Variables Based on a Control

This article describes how to create a set of dynamic variables for the current and previous waves based on the period selected in a control box:

Requirements

• A data set that includes a Nominal wave variable. In this example, we have a variable called Wave that tells us what quarter the survey was completed.
• A Control that includes the items from the wave variable. Here, we have data for Qtr 1 to Qtr 4. As we are interested in the current and previous waves, we have omitted Qtr 1 from our wave.combo.box control.

Method

1. Select your data set in the Data Sources tree.

2. Go to the Anything icon > Data > Variables > New > Custom Code > R > Numeric in the toolbar.

3. Paste the below into the R Code editor:

waves = Wave 
unique.waves = levels(waves) #Get wave categories
curr.index = match(wave.combo.box,unique.waves) #Find index of current wave
waves %in% unique.waves[curr.index-1] #Return TRUE for previous wave

• The above code gets the levels or categories from the Wave variable and defines them as unique.waves.
• It then finds the index of the current wave selected in the control box within unique.waves. Note, this code assumes the waves are in the correct order.
• Finally, we return TRUE or FALSE based on whether the data matches the previous wave category.

4. Update Name and Label under General > General to Previous, for example.

5. Right-click the variable in the Data Sources tree and select Duplicate to copy this variable.

6. Replace the R code in the duplicated variable with the below:

Wave %in% wave.combo.box

This will simply return TRUE if the data in our Wave variable matches the category selected in the control box.

7. Update Name and Label under General > General to Current, for example.

8. Select both variables in the Data Sources tree, and right-click > Combine.

9. Update the variable set Label in the object inspector to Waves, for example.

10. Change Structure to Binary - Multi: Non-mutually exclusive categories.

See Also

How to Work with R in Displayr

How to Create a Custom Numeric R Variable

How to Work with Date Ranges Using R