routine invert
Documentation for routine invert
assembled from the following types:
role Baggy
From Baggy
(Baggy) method invert
Defined as:
method invert(Baggy: --> Seq)
Returns all elements and their respective weights as a Seq of Pairs, where the element itself is the value and the weight of that element is the key, i.e. the opposite of method pairs. Except for some esoteric cases invert
on a Baggy type returns the same result as antipairs.
my = bag <bacon eggs bacon>;my = .invert;say .sort; # OUTPUT: «(1 => eggs 2 => bacon)»
class RaceSeq
From RaceSeq
(RaceSeq) method invert
method invert(RaceSeq:)
Inverts the RaceSeq
created from a Seq
by .race
.
class HyperSeq
From HyperSeq
(HyperSeq) method invert
method invert(HyperSeq:)
Inverts the HyperSeq
created from a Seq
by .hyper
.
class Any
From Any
(Any) method invert
Defined as:
multi method invert(Any:)multi method invert(Any:)
Applied to a type object will return an empty list; applied to an object will convert it to a list and apply List.invert
to it, that is, interchange key with value in every Pair. The resulting list needs to be a list of Pair
s.
"aaabbcccc".comb.Bag.invert.say; # OUTPUT: «(4 => c 3 => a 2 => b)»
In this case, a Bag
can be converted to a list of Pair
s. If the result of converting the object to a list is not a list of pairs, the method will fail.
class Map
From Map
(Map) method invert
Defined as:
method invert(Map: --> Seq)
Returns all keys and their respective values as a Seq of Pair
s where the keys and values have been exchanged. The difference between invert
and antipairs is that invert
expands list values into multiple pairs.
my = Map.new('a' => (2, 3), 'b' => 17);say .invert; # OUTPUT: «(2 => a 3 => a 17 => b)»
class Pair
From Pair
(Pair) method invert
Defined as:
method invert(Pair: --> Seq)
Returns a Seq. If the .value
of the invocant is NOT an Iterable, the Seq will contain a single Pair whose .key
is the .value
of the invocant and whose .value
is the .key
of the invocant:
:foo<bar>.invert.perl.say; # OUTPUT: «(:bar("foo"),).Seq»
If invocant's .value
is an Iterable, the returned Seq will contain the same number of Pairs as items in the .value
, with each of those items a .key
of a pair and the .key
of the invocant the .value
of that pair:
:foo<Perl is great>.invert.perl.say;# OUTPUT: «(:Perl("foo"), :is("foo"), :great("foo")).Seq»:foo.invert.perl.say;# OUTPUT: «((:a(42)) => "foo", (:b(72)) => "foo").Seq»
To perform the exact .key
and .value
swap, use .antipair
method.
class List
From List
(List) routine invert
Defined as:
method invert(List: --> Seq)
Assumes every element of the List is a Pair
. Returns all elements as a Seq of Pair
s where the keys and values have been exchanged. If the value of a Pair
is an Iterable
, then it will expand the values of that Iterable
into separate pairs.
my = List.new('a' => (2, 3), 'b' => 17);say .invert; # OUTPUT: «(2 => a 3 => a 17 => b)»