One feature of transformations is the ability to replace set values in a particular column with text of the user's choosing.
The Select drop-down menu will display each of the unified attributes chosen by the user in the schema mapping stage. From there, the user can choose to replace either all values or empty values with a string.
The user can also specify which records this will apply to. The options are records from the entire unified dataset, or only records from specific source datasets.
Consider the example where the user wishes to replace all empty birthdates with the string "Unknown". Before applying the transformation, this field was 30% empty.
Using the fill tool as shown, the user can specify how they wish to update the unified dataset.
After clicking Show all, the preview of the dob attribute has been updated. If the user is happy with the transformation, they can save it.
This transformation will be applied across the unified dataset and appear in any exports.