ColumnExpressionSequence¶

class lsst.daf.relation.ColumnExpressionSequence(items: Sequence[ColumnExpression], dtype: type | None)¶

A container expression backed by a sequence of scalar column expressions.

Attributes Summary

columns_required Columns required by this expression (Set [ ColumnTag ]).

Methods Summary

`contains`(item)	Construct a boolean column expression that tests whether a scalar expression is present in this container expression.
`is_supported_by`(engine)	Test whether the given engine is capable of evaluating this expression.
`range_literal`(r)	Construct a container expression from a range of indices.
`sequence`(items, dtype)	Construct a container expression from a sequence of item expressions.

Attributes Documentation

columns_required¶

Columns required by this expression (Set [ ColumnTag ]).

This includes columns required by expressions nested within this one.

Methods Documentation

contains(item: ColumnExpression) → ColumnInContainer¶

Construct a boolean column expression that tests whether a scalar expression is present in this container expression.

Parameters:	item : `ColumnExpression` Item expression to test.
Returns:	contains : `ColumnInContainer` Boolean column expression that tests for membership in the container.

is_supported_by(engine: Engine) → bool¶

Test whether the given engine is capable of evaluating this expression.

Parameters:	engine : `Engine` Engine to test.
Returns:	supported : `bool` Whether the engine supports this expression and all expressions nested within it.

classmethod range_literal(r: range) → lsst.daf.relation._columns._container.ColumnRangeLiteral¶

Construct a container expression from a range of indices.

Parameters:	r : `range` Range object.
Returns:	container : `ColumnRangeLiteral` Container expression object representing the range.

classmethod sequence(items: Sequence[ColumnExpression], dtype: type | None = None) → ColumnExpressionSequence¶

Construct a container expression from a sequence of item expressions.

Parameters:	items : `Sequence` [ `ColumnExpression` ] Sequence of item expressions. dtype : `type`, optional The Python type of the elements in the container.
Returns:	container : `ColumnExpressionSequence` Container expression object backed by the given items.