key_set

Python port of KeySet in TypeScript and KeySet in Ruby

KeySet with 4 classes to represent concepts of All, None, Some, and AllExceptSome, the last 2 with a set of keys, and all with intersection, difference, union, inversion, and inclusion calculations.

Limitations

• for now, only KeySet of strings
• no ComposedKeySet yet (see KeySet in TypeScript)

KeySetType enum

Enum that represents the 4 types of KeySets:

• ALL represents the entirety of possible keys (𝕌)
• NONE represents an empty set (∅)
• SOME represents a concrete set (A ⊂ 𝕌)
• ALL_EXCEPT_SOME represents the complementary of a set, all the elements except the given ones (A' = {x ∈ 𝕌 | x ∉ A}) _(see Complement in Wikipedia)*

Creation

Build your KeySets using the build functions

from key_set import build_all, build_none, build_some_or_none, build_all_except_some_or_all

build_all()  # => returns a new instance of KeySetAll
build_none()  # => returns a new instance of KeySetNone

build_some_or_none([])  # returns a new instance of KeySetNone

# returns a new instance of KeySetSome with keys {'a', 'b', 'c'} (in a unique set)
build_some_or_none({'a', 'c', 'b'})
build_some_or_none(['a', 'c', 'b', 'c'])

build_all_except_some_or_all([])  # returns a new instance of KeySetAll

# returns a new instance of KeySetAllExceptSome with keys {'a', 'b', 'c'} (in a unique set)
build_all_except_some_or_all({'a', 'c', 'b'})
build_all_except_some_or_all(['a', 'c', 'b', 'c'])

KeySet classes

Methods exposed:

key_set_type()

returns the KeySetType enum

elements()

returns the set with the elements. It will be blank for All and None.

represents_xxx() methods

• represents_all: returns True if the KeySet is ALL
• represents_none: returns True if the KeySet is NONE
• represents_some: returns True if the KeySet is SOME
• represents_all_except_some: returns True if the KeySet is ALL_EXCEPT_SOME

invert()

Returns a new KeySet that represents the inverse Set of this one.

• ALL <-> NONE
• SOME <-> ALL_EXCEPT_SOME

intersect(other)

Returns a new KeySet with the intersection (A ∩ B) of both Sets: a set that contains the elements included in both sets.

union(other)

Returns a new KeySet with the union (A ∩ B) of both Sets: a set that contains the elements in any of the sets.

difference(other)

Returns a new KeySet with the difference (A - B) of the Sets: a set that contains the elements of A that are not in B.

includes(element)

Returns True if the set that this KeySet represents contains the given element.