traits.trait_set_object Module

Classes

class traits.trait_set_object.TraitSetEvent(*, removed=None, added=None)

An object reporting in-place changes to a traits sets.

Parameters:

• removed (set, optional) – Old values that were removed from the set.

• added (set, optional) – New values added to the set.

removed

Old values that were removed from the set.

Type:

set

added

New values added to the set.

Type:

set

class traits.trait_set_object.TraitSet(*args, **kwargs)

A subclass of set that validates and notifies listeners of changes.

Parameters:

• value (iterable, optional) – Iterable providing the items for the set.

• item_validator (callable, optional) – Called to validate and/or transform items added to the set. The callable should accept a single item and return the transformed item, raising TraitError for invalid items. If not given, no item validation is performed.

• notifiers (list of callable, optional) –

  A list of callables with the signature:

  notifier(trait_set, removed, added)
  

  Where ‘added’ is a set containing new values that have been added. And ‘removed’ is a set containing old values that have been removed.

  If this argument is not given, the list of notifiers is initially empty.

item_validator

Called to validate and/or transform items added to the set. The callable should accept a single item and return the transformed item, raising TraitError for invalid items.

Type:

callable

notifiers

A list of callables with the signature:

notifier(trait_set, removed, added)

where ‘added’ is a set containing new values that have been added and ‘removed’ is a set containing old values that have been removed.

Type:

list of callable

notify(removed, added)

Call all notifiers.

This simply calls all notifiers provided by the class, if any. The notifiers are expected to have the signature:

notifier(trait_set, removed, added)

Any return values are ignored. Any exceptions raised are not handled. Notifiers are therefore expected not to raise any exceptions under normal use.

Parameters:

• removed (set) – The items that have been removed.

• added (set) – The new items that have been added to the set.

add(value)

Add an element to a set.

This has no effect if the element is already present.

Parameters:

value (any) – The value to add to the set.

clear()

Remove all elements from this set.

discard(value)

Remove an element from the set if it is a member.

If the element is not a member, do nothing.

Parameters:

value (any) – An item in the set

difference_update(*args)

Remove all elements of another set from this set.

Parameters:

args (iterables) – The other iterables.

intersection_update(*args)

Update the set with the intersection of itself and another set.

Parameters:

args (iterables) – The other iterables.

pop()

Remove and return an arbitrary set element.

Raises KeyError if the set is empty.

Returns:

item – An element from the set.

Return type:

any

Raises:

KeyError – If the set is empty.

remove(value)

Remove an element that is a member of the set.

If the element is not a member, raise a KeyError.

Parameters:

value (any) – An element in the set

Raises:

KeyError – If the value is not found in the set.

symmetric_difference_update(value)

Update the set with the symmetric difference of itself and another.

Parameters:

value (iterable)

update(*args)

Update the set with the union of itself and others.

Parameters:

args (iterables) – The other iterables.

class traits.trait_set_object.TraitSetObject(*args, **kwargs)

A specialization of TraitSet with a default validator and notifier for compatibility with Traits versions before 6.0.

Parameters:

• trait (CTrait) – The trait that the set has been assigned to.

• object (HasTraits) – The object this set belongs to. Can also be None in cases where the set has been disconnected from its HasTraits parent.

• name (str) – The name of the trait on the object.

• value (iterable) – The initial value of the set.

trait

The trait that the set has been assigned to.

Type:

CTrait

object

A callable that when called with no arguments returns the HasTraits object that this set belongs to, or None if there is no such object.

Type:

callable

name

The name of the trait on the object.

Type:

str

value

The initial value of the set.

Type:

iterable

notifier(trait_set, removed, added)

Converts and consolidates the parameters to a TraitSetEvent and then fires the event.

Parameters:

• trait_set (set) – The complete set

• removed (set) – Set of values that were removed.

• added (set) – Set of values that were added.