NamedValueSet

class lsst.daf.butler.core.utils.NamedValueSet(elements: Iterable[T] = ())

Bases: collections.abc.MutableSet, typing.Generic

A custom mutable set class that requires elements to have a .name attribute, which can then be used as keys in dict-like lookup.

Names and elements can both be used with the in and del operators, remove, and discard. Names (but not elements) can be used with []-based element retrieval (not assignment) and the get method. pop can be used in either its MutableSet form (no arguments; an arbitrary element is returned) or its MutableMapping form (one or two arguments for the name and optional default value, respectively).

Parameters

elementsiterable

Iterable over elements to include in the set.

Raises

AttributeError

Raised if one or more elements do not have a .name attribute.

Notes

Iteration order is guaranteed to be the same as insertion order (with the same general behavior as dict ordering). Like dicts, sets with the same elements will compare as equal even if their iterator order is not the same.

Attributes Summary

names

The set of element names, in the same order (KeysView).

Methods Summary

add(element)	Add an element to the set.
asDict()	Return a mapping view with names as keys.
clear()	This is slow (creates N new iterators!) but effective.
copy()
discard(element)	Remove an element from the set if it exists.
freeze()	Disable all mutators, effectively transforming self into an immutable set.
get(name[, default])	Return the element with the given name, or default if no such element is present.
isdisjoint(other)	Return True if two sets have a null intersection.
issubset(other)
issuperset(other)
pop(*args)	Remove and return an element from the set.
remove(element)	Remove an element from the set.

Attributes Documentation

names

The set of element names, in the same order (KeysView).

Methods Documentation

add(element: T)

Add an element to the set.

Raises

AttributeError

Raised if the element does not have a .name attribute.

asDict() → Mapping[str, T]

Return a mapping view with names as keys.

Returns

dictMapping

A dictionary-like view with values() == self.

clear()

This is slow (creates N new iterators!) but effective.

copy() → lsst.daf.butler.core.utils.NamedValueSet[~T][T]

discard(element: Union[str, T])

Remove an element from the set if it exists.

Does nothing if no matching element is present.

Parameters

elementobject or str

Element to remove or the string name thereof. Assumed to be an element if it has a .name attribute.

freeze()

Disable all mutators, effectively transforming self into an immutable set.

get(name: str, default=None)

Return the element with the given name, or default if no such element is present.

isdisjoint(other)

Return True if two sets have a null intersection.

issubset(other)

issuperset(other)

pop(*args)

Remove and return an element from the set.

Parameters

namestr, optional

Name of the element to remove and return. Must be passed positionally. If not provided, an arbitrary element is removed and returned.

defaultobject, optional

Value to return if name is provided but no such element exists.

Raises

KeyError

Raised if name is provided but default is not, and no matching element exists.

remove(element: Union[str, T])

Remove an element from the set.

Parameters

elementobject or str

Element to remove or the string name thereof. Assumed to be an element if it has a .name attribute.

Raises

KeyError

Raised if an element with the given name does not exist.