Column accessors API

Edit page Last modified: 14 January 2025

For frequently accessed columns type casting can be reduced by Column Accessors:

val survived by column<Boolean>() // accessor for Boolean column with name 'survived'
val home by column<String>()
val age by column<Int?>()
val name by column<String>()
val lastName by column<String>()

Now columns can be accessed in a type-safe way using invoke operator:

DataFrame.read("titanic.csv")
    .add(lastName) { name().split(",").last() }
    .dropNulls { age }
    .filter { survived() && home().endsWith("NY") && age()!! in 10..20 }

The titanic.csv file can be found here.

warning

Note that it still doesn’t solve the problem of whether the column actually exists in a data frame, but reduces type casting.