CollectionSearch

class lsst.daf.butler.CollectionSearch(collections: Tuple[str, ...])

Bases: collections.abc.Sequence, typing.Generic

An ordered search path of collections.

The fromExpression method should almost always be used to construct instances, as the regular constructor performs no checking of inputs (and that can lead to confusing error messages downstream).

Parameters:

collections : tuple [ str ]

Tuple of collection names, ordered from the first searched to the last searched.

Notes

A CollectionSearch is used to find a single dataset (or set of datasets with different dataset types or data IDs) according to its dataset type and data ID, giving preference to collections in the order in which they are specified. A CollectionQuery can be constructed from a broader range of expressions but does not order the collections to be searched.

CollectionSearch is an immutable sequence of str collection names.

A CollectionSearch instance constructed properly (e.g. via fromExpression) is a unique representation of a particular search path; it is exactly the same internally and compares as equal to any CollectionSearch constructed from an equivalent expression, regardless of how different the original expressions appear.

Methods Summary

count(value)
fromExpression(expression)	Process a general expression to construct a CollectionSearch instance.
index(value, [start, [stop]])	Raises ValueError if the value is not present.
iter(manager, *, datasetType, …)	Iterate over collection records that match this instance and the given criteria, in order.

Methods Documentation

count(value) → integer -- return number of occurrences of value

classmethod fromExpression(expression: Any) → lsst.daf.butler.registry.wildcards.CollectionSearch

Process a general expression to construct a CollectionSearch instance.

Parameters:

expression

May be:

• a str collection name;
• an iterable of str collection names;
• another CollectionSearch instance (passed through unchanged).

Duplicate entries will be removed (preserving the first appearance of each collection name).

Returns

——-

collections : CollectionSearch

A CollectionSearch instance.

index(value[, start[, stop]]) → integer -- return first index of value.

Raises ValueError if the value is not present.

Supporting start and stop arguments is optional, but recommended.

iter(manager: CollectionManager, *, datasetType: Optional[DatasetType] = None, collectionTypes: AbstractSet[CollectionType] = frozenset({<CollectionType.RUN: 1>, <CollectionType.TAGGED: 2>, <CollectionType.CHAINED: 3>, <CollectionType.CALIBRATION: 4>}), done: Optional[Set[str]] = None, flattenChains: bool = True, includeChains: Optional[bool] = None) → Iterator[CollectionRecord]

Iterate over collection records that match this instance and the given criteria, in order.

This method is primarily intended for internal use by Registry; other callers should generally prefer Registry.findDatasets or other Registry query methods.

Parameters:

manager : CollectionManager

Object responsible for managing the collection tables in a Registry.

collectionTypes : AbstractSet [ CollectionType ], optional

If provided, only yield collections of these types.

done : set, optional

A set containing the names of all collections already yielded; any collections whose names are already present in this set will not be yielded again, and those yielded will be added to it while iterating. If not provided, an empty set will be created and used internally to avoid duplicates.

flattenChains : bool, optional

If True (default) recursively yield the child collections of CHAINED collections.

includeChains : bool, optional

If False, return records for CHAINED collections themselves. The default is the opposite of flattenChains: either return records for CHAINED collections or their children, but not both.

Yields:

record : CollectionRecord

Matching collection records.