core/org.jetbrains.kotlinx.dataframe.schema/ColumnSchema

ColumnSchema

Describes a single column of a DataFrameSchema: what kind of column it is, what type it holds, and, for the two nested kinds, the schema of what is inside it.

There is one subclass per column kind:

Value — a value column, described by the common type of its values.
Group — a column group, described by the schema of its nested columns.
Frame — a frame column, described by the schema of the dataframes it holds.

Inheritors

Value

Group

Frame

Constructors

ColumnSchema

protected constructor()

Types

Frame

class Frame(val schema: DataFrameSchema, val nullable: Boolean, val contentType: KType?) : ColumnSchema

The schema of a frame column.

Group

class Group(val schema: DataFrameSchema, val contentType: KType?) : ColumnSchema

The schema of a column group.

Value

class Value(val type: KType) : ColumnSchema

The schema of a value column.

Properties

contentType

abstract val contentType: KType?

The type associated with the contents of the column. For Value this is irrelevant and thus null. Use type instead. For Group this is the common base type associated with all the DataRows in the column. For Frame this is the common base type associated with all the DataFrames in the column.

kind

abstract val kind: ColumnKind

Either Value or Group or Frame.

nullable

abstract val nullable: Boolean

Whether the column is nullable. Is always false for Group.

type

abstract val type: KType

The type of the column. For Value this is the common base type associated with all the values in the column. For Group this is AnyRow. For Frame this is AnyFrame.

Functions

compare

fun compare(other: ColumnSchema, comparisonMode: ComparisonMode = LENIENT): CompareResult

Compares this column schema with the other column schema.

createEmptyColumn

internal fun ColumnSchema.createEmptyColumn(name: String): AnyCol

Create "empty" column based on the toplevel of this ColumnSchema.

createNullFilledColumn

internal fun ColumnSchema.createNullFilledColumn(name: String, numberOfRows: Int): AnyCol

Creates a column based on this ColumnSchema filled with null or empty dataframes.

equals

open operator override fun equals(other: Any?): Boolean

Checks equality by kind, type, or schema

hashCode

open override fun hashCode(): Int