toList

Converts DataFrame into a List of data class instances by current DataFrame type argument.

toList()

More info: Interop with Collections

Type of data class is defined by current type argument of DataFrame. If this type argument is not data class, exception will be thrown.

Data class properties are matched with DataFrame columns by name. If property type differs from column type type conversion will be performed. If no automatic type conversion was found, exception will be thrown.

To export DataFrame into specific type of data class, use toListOf:

val df = dataFrameOf("name", "lastName", "age")("John", "Doe", 21)
    .group("name", "lastName").into("fullName")

data class FullName(val name: String, val lastName: String)

data class Person(val fullName: FullName, val age: Int)

val persons = df.toListOf<Person>() // [Person(fullName = FullName(name = "John", lastName = "Doe"), age = 21)]