gravitino.api.expressions.transforms.transform.Transform

class gravitino.api.expressions.transforms.transform.Transform

Bases: Expression, ABC

Represents a transform function in the public logical expression API.

For example, the transform date(ts) is used to derive a date value from a timestamp column. The transform name is “date” and its argument is a reference to the “ts” column.

__init__()

Methods

__init__()
arguments()	Gets the arguments passed to the transform function.
assignments()	Gets the preassigned partitions in the partitioning.
children()	Returns a list of the children of this node.
name()	Gets the transform function name.
references()	Returns a list of fields or columns that are referenced by this expression.

Attributes

EMPTY_EXPRESSION	EMPTY_EXPRESSION is only used as an input when the default children method builds the result.
EMPTY_NAMED_REFERENCE	EMPTY_NAMED_REFERENCE is only used as an input when the default references method builds the result array to avoid repeatedly allocating an empty array.

EMPTY_EXPRESSION: List[Expression] = []

EMPTY_EXPRESSION is only used as an input when the default children method builds the result.

EMPTY_NAMED_REFERENCE: List[NamedReference] = []

EMPTY_NAMED_REFERENCE is only used as an input when the default references method builds the result array to avoid repeatedly allocating an empty array.

abstract arguments() → List[Expression]

Gets the arguments passed to the transform function.

Returns:

List[Expression]: The arguments passed to the transform function.

assignments() → List[Partition]

Gets the preassigned partitions in the partitioning.

Currently, only Transforms.ListTransform and Transforms.RangeTransform need to deal with assignments

Returns:

List[Partition]: The preassigned partitions in the partitioning.

children() → List[Expression]

Returns a list of the children of this node. Children should not change.

abstract name() → str

Gets the transform function name.

Returns:

str: The transform function name.

references() → List[NamedReference]

Returns a list of fields or columns that are referenced by this expression.