Extension Properties API

Auto-generated extension properties are the safest and easiest way to access columns in a DataFrame. They are generated based on a dataframe schema, with the name and type of properties inferred from the name and type of the corresponding columns.

Having these, it allows you to work with your dataframe like:

val peopleDf /* : DataFrame<Person> */ = DataFrame.read("people.csv").cast<Person>()
val nameColumn /* : DataColumn<String> */ = peopleDf.name
val ageColumn /* : DataColumn<Int> */ = peopleDf.personData.age

and of course

peopleDf.add("lastName") { name.split(",").last() }
    .dropNulls { personData.age }
    .filter { survived && home.endsWith("NY") && personData.age in 10..20 }

To find out how to use this API in your environment, check out Working with Data Schemas or jump straight to Data Schemas in Gradle projects, or Data Schemas in Jupyter notebooks.