Dataframes: displaying categorical key when displaying a dataframe while saving the value in the data array

There isn’t a good package for this. The package ReadStatTables.jl has a LabelledArray type that implements Stata-like labeling (which is basically what you are asking for). But it’s not available on its own. Someone needs to split that type out into its own package so people can use it without the full ReadStatTables.jl dependency.