How to Create a Categorical Variable from a Date/Time Variable

There are some limitations to using Date/Time variables in Displayr.

• It's not possible to specify column comparisons using date variables.
• It's also not possible to have irregular dates (e.g., one column representing a year, a second column representing a quarter).
• You cannot create filters for each time period.

However, these can be achieved by creating an ordinal (or nominal) variable from the date variable.

Requirements

• Familiarity with the Structure and Value Attributes of Variable Sets.

Method - Create categories based on the date aggregation

1. Select the date/time variable from Data Sources.
2. Press Date/Time in the object inspector and modify the settings. For example, if you want to create months and quarters, you would set Aggregation to 1 Month.
3. Press OK.
4. Select any variable in the Data Sources tree, and click + > Custom Code > R > Nominal.
5. In the Code Editor, paste in the following code and change date_var to the name of your Date/Time variable :
   attr(date_var,"QDate")

Method - Create categories for each underlying date in the data

If you have only a few different dates, the simplest approach is to click on the date/time variable and change its Structure to Ordinal. This will create a new category for every unique date/time value. Often this leads to too many categories to be useful, though, and so Method 2 is preferred.

Additional Notes

After you create your new categorical variable:

• You can specify which columns to be tested, see How to Specify Columns to be Compared in a Table.
• You can create a table and Combine and Create NET across categories create any irregular dates.
• You can use the Filter > Filters from Selected Data automation to create a filter for each time period category.