Data appears to contain only numbers, but these numbers are codes for values of categorical variables.
This dataset is open in the PSPP statistical analysis application.
The same dataset with labels instead of numeric codes.
You can switch back and forth between these two display options using the menu.
Although the data is stored as numbers, the labels allow you to see what the data means.
In the figure, you are looking at it in the data editor. You also can set up an analysis or view the results.
You can include comments in a dataset.
You may also find other types of data labels in data-mining applications. The native data format for Weka allows you to include comments in a dataset. This gives you a good place to put annotations about the source of the data and other important details.
You can annotate data.
RapidMiner also has an option for annotations. You can use the graphic user interface to enter annotations for individual rows of data.