role Setty
role Setty does QuantHash { }
A role for collections which make sure that each element can only appear once. See Set and SetHash.
Methods
method new-from-pairs
method new-from-pairs(*@pairs --> Setty:D)
Constructs a Setty object from a list of Pair objects given as positional arguments:
say Set.new-from-pairs: 'butter' => 0.22, 'salt' => 0, 'sugar' => 0.02;
# OUTPUT: «Set(butter sugar)»
Note: be sure you aren't accidentally passing the Pairs as positional arguments; the quotes around the keys in the above example are significant.
method grab
method grab($count = 1)
Removes and returns $count elements chosen at random (without repetition)
from the set.
If * is passed as $count, or $count is greater than or equal to the
size of the set, then all its elements are removed and returned in random order.
Only works on mutable sets; When used on an immutable set, it results in an exception.
method grabpairs
method grabpairs($count = 1)
Removes $count elements chosen at random (without repetition) from the set,
and returns a list of Pair objects whose keys are the grabbed elements and
whose values are True.
If * is passed as $count, or $count is greater than or equal to the
size of the set, then all its elements are removed and returned as Pairs in
the aforementioned way in random order.
Only works on mutable sets; When used on an immutable set, it results in an exception.
method pick
multi method pick($count = 1)
Returns $count elements chosen at random (without repetition) from the set.
If * is passed as $count, or $count is greater than or equal to the
size of the set, then all its elements are returned in random order (shuffled).
method pickpairs
multi method pickpairs(Setty:D: --> Pair:D)
multi method pickpairs(Setty:D: $count --> Seq:D)
Returns a Pair or a Seq of Pairs depending on the candidate of the method
being invoked. Each Pair returned has an element of the invocant as its key and
True as its value. In contrast to grabpairs, the elements
are 'picked' without replacement.
If * is passed as $count, or $count is greater than or equal to the number
of elements of the invocant, then all element/True Pairs from
the invocant are returned in a random sequence; i.e. they are returned shuffled;
Note that each pickpairs invocation maintains its own private state and has
no effect on subsequent pickpairs invocations.
my $numbers = set (4, 2, 3);
say $numbers.pickpairs; # OUTPUT: «4 => True»
say $numbers.pickpairs(1); # OUTPUT: «(3 => True)»
say $numbers.pickpairs(*); # OUTPUT: «(2 => True 4 => True 3 => True)»
method roll
multi method roll($count = 1)
Returns a lazy list of $count elements, each randomly selected from the set.
Each random choice is made independently, like a separate die roll where each
die face is a set element.
If * is passed as $count, the list is infinite.
method antipairs
multi method antipairs(Setty:D: --> Seq:D)
Returns all elements in the set and True as a Seq of Pairs,
where the element itself is the value, i.e. the opposite of method pairs.
my $s = Set.new(1, 2, 3, 1);
say $s.antipairs.sort; # OUTPUT: «(True => 1 True => 2 True => 3)»
method keys
multi method keys(Setty:D: --> Seq:D)
Returns a Seq of all elements of the set.
my $s = Set.new(1, 2, 3);
say $s.keys; # OUTPUT: «(3 1 2)»
method values
multi method values(Setty:D: --> Seq:D)
Returns a Seq containing as many True values as the set has elements.
my $s = Set.new(1, 2, 3);
say $s.values; # OUTPUT: «(True True True)»
method kv
multi method kv(Setty:D: --> Seq:D)
Returns a Seq of the set's elements and True values interleaved.
my $s = Set.new(1, 2, 3);
say $s.kv; # OUTPUT: «(3 True 1 True 2 True)»
method elems
method elems(Setty:D: --> Int)
The number of elements of the set.
method total
method total(Setty:D: --> Int)
The total of all the values of the QuantHash object. For a Setty
object, this is just the number of elements.
method minpairs
multi method minpairs(Setty:D: --> Seq:D)
Returns the value of self.pairs (as all Pairs have minimum values). See also Any.minpairs
method maxpairs
multi method maxpairs(Setty:D: --> Seq:D)
Returns the value of self.pairs (as all Pairs have maximum values). See also Any.maxpairs
method default
method default(--> False)
Returns the default value of the invocant, i.e. the value which is returned
when trying to access an element in the Setty object which has not been
previously initialized or when accessing an element which has explicitly
been set to Nil or False.
my $s1 = SetHash.new(1, 2, 3);
say $s1{2}; # OUTPUT: «True»
$s1{2} = Nil;
say $s1{2}; # OUTPUT: «False»
# access non initialized element
say $s1{4}; # OUTPUT: «False»
method ACCEPTS
method ACCEPTS($other)
Returns True if $other and self contain all the same elements,
and no others.
method Bag
method Bag(Setty:D: --> Bag:D)
Returns a Bag containing the elements of the invocant.
my Bag $b = Set.new(1, 2, 3).Bag;
say $b; # OUTPUT: «Bag(3 1 2)»
The quantity of the elements in this created bag will be set to one:
say (1,2,3).Bag{1}; # OUTPUT: «1»
method BagHash
method BagHash(Setty:D: --> BagHash:D)
Returns a BagHash containing the elements of the invocant.
my BagHash $b = Set.new(1, 2, 3).BagHash;
say $b; # OUTPUT: «BagHash(1 2 3)»
method Bool
multi method Bool(Setty:D: --> Bool:D)
Returns True if the invocant contains at least one element.
my $s1 = Set.new(1, 2, 3);
say $s1.Bool; # OUTPUT: «True»
my $s2 = $s1 ∩ Set.new(4, 5); # set intersection operator
say $s2.Bool; # OUTPUT: «False»
method Mix
method Mix(Setty:D: --> Mix:D)
Returns a Mix containing the elements of the invocant.
my Mix $b = Set.new(1, 2, 3).Mix;
say $b; # OUTPUT: «Mix(3 1 2)»
The elements of the returned Mix will have weights equal to 1:
say (1,2,3).Mix{3}; # OUTPUT: «1»
method MixHash
method MixHash(Setty:D: --> MixHash:D)
Returns a MixHash containing the elements of the invocant.
my MixHash $b = Set.new(1, 2, 3).MixHash;
say $b; # OUTPUT: «MixHash(1 2 3)»