RowSequence

class lsst.daf.relation.iteration.RowSequence(rows: Sequence[Mapping[ColumnTag, Any]])

Bases: MaterializedRowIterable

A RowIterable backed by a Sequence

Parameters:
rowsMapping

Sequence of rows, where each row is (as usual for RowIterable types) a Mapping with ColumnTag keys.

Methods Summary

materialized()

Convert this iterable to one that holds its rows in a Python collection of some kind, instead of generating them lazily.

sliced(start, stop)

Apply a slice operation to this RowIterable.

to_mapping(unique_key)

Convert this iterable to a RowMapping, unless it already is one.

to_sequence()

Convert this iterable to a RowSequence, unless it already is one.

Methods Documentation

materialized() MaterializedRowIterable

Convert this iterable to one that holds its rows in a Python collection of some kind, instead of generating them lazily.

Returns:
rowsMaterializedRowIterable

A RowIterable that isn’t lazy.

sliced(start: int, stop: int | None) RowIterable

Apply a slice operation to this RowIterable.

Parameters:
startint

Start index.

stopint or None

Stop index (one-past-the-end), or None to include up through the last row.

Returns:
rowsRowIterable

Iterable representing the slice. May or may not be lazy.

to_mapping(unique_key: Sequence[ColumnTag]) RowMapping

Convert this iterable to a RowMapping, unless it already is one.

Parameters:
unique_keySequence [ ColumnTag ]

Sequence of columns to extract into a tuple to use as keys in the mapping, guaranteeing uniqueness over these columns.

Returns:
rowsRowMapping

A RowIterable backed by a mapping.

to_sequence() RowSequence

Convert this iterable to a RowSequence, unless it already is one.

Returns:
rowsRowSequence

A RowIterable backed by a sequence.