struct Set(T)

Overview

Set implements a collection of values with no duplicates.

AnEnumerable object can be converted toSet using the#to_set method.

Set usesHash as storage, so you must note the following points:

Example

s1 = Set{1, 2}
s2 = [1, 2].to_set
s3 = Set.new [1, 2]
s1 == s2 # => true
s1 == s3 # => true
s1.add(2)
s1.concat([6, 8])
s1.subset_of? s2 # => false
s2.subset_of? s1 # => true

Included Modules

Defined in:

json/to_json.cr
set.cr
yaml/to_yaml.cr

Constructors

Instance Method Summary

Instance methods inherited from module Iterable(T)

chunk(reuse = false, &block : T -> U) forall U chunk, chunk_while(reuse : Bool | Array(T) = false, &block : T, T -> B) forall B chunk_while, cycle(n)
cycle cycle, each each, each_cons(count : Int, reuse = false) each_cons, each_cons_pair each_cons_pair, each_slice(count : Int, reuse = false) each_slice, each_step(n : Int)
each_step(n : Int, *, offset : Int) each_step, each_with_index(offset = 0) each_with_index, each_with_object(obj) each_with_object, slice_after(reuse : Bool | Array(T) = false, &block : T -> B) forall B
slice_after(pattern, reuse : Bool | Array(T) = false) slice_after, slice_before(reuse : Bool | Array(T) = false, &block : T -> B) forall B
slice_before(pattern, reuse : Bool | Array(T) = false) slice_before, slice_when(reuse : Bool | Array(T) = false, &block : T, T -> B) forall B slice_when

Instance methods inherited from module Enumerable(T)

accumulate(initial : U) : Array(U) forall U
accumulate : Array(T)
accumulate(initial : U, &block : U, T -> U) : Array(U) forall U
accumulate(&block : T, T -> T) : Array(T) accumulate, all?(& : T -> ) : Bool
all?(pattern) : Bool
all? : Bool all?, any?(& : T -> ) : Bool
any?(pattern) : Bool
any? : Bool any?, chunks(&block : T -> U) forall U chunks, compact_map(& : T -> _) compact_map, count(& : T -> ) : Int32
count(item) : Int32 count, cycle(n, & : T -> ) : Nil
cycle(& : T -> ) : Nil cycle, each(& : T -> ) each, each_cons(count : Int, reuse = false, &) each_cons, each_cons_pair(& : T, T -> ) : Nil each_cons_pair, each_slice(count : Int, reuse = false, &) each_slice, each_step(n : Int, *, offset : Int = 0, & : T -> ) : Nil each_step, each_with_index(offset = 0, &) each_with_index, each_with_object(obj : U, & : T, U -> ) : U forall U each_with_object, empty? : Bool empty?, find(if_none = nil, & : T -> ) find, find!(& : T -> ) : T find!, find_value(if_none = nil, & : T -> ) find_value, first(&)
first(count : Int) : Array(T)
first : T first, first? : T | Nil first?, flat_map(& : T -> _) flat_map, group_by(& : T -> U) forall U group_by, in_groups_of(size : Int, filled_up_with : U = nil) forall U
in_groups_of(size : Int, filled_up_with : U = nil, reuse = false, &) forall U in_groups_of, in_slices_of(size : Int) : Array(Array(T)) in_slices_of, includes?(obj) : Bool includes?, index(& : T -> ) : Int32 | Nil
index(obj) : Int32 | Nil index, index!(& : T -> ) : Int32
index!(obj) : Int32 index!, index_by(& : T -> U) : Hash(U, T) forall U index_by, join(io : IO, separator = "") : Nil
join(separator, io : IO) : Nil
join(separator = "") : String
join(io : IO, separator = "", & : T, IO -> )
join(separator, io : IO, &)
join(separator = "", & : T -> ) join, map(& : T -> U) : Array(U) forall U map, map_with_index(offset = 0, & : T, Int32 -> U) : Array(U) forall U map_with_index, max(count : Int) : Array(T)
max : T max, max? : T | Nil max?, max_by(& : T -> U) : T forall U max_by, max_by?(& : T -> U) : T | Nil forall U max_by?, max_of(& : T -> U) : U forall U max_of, max_of?(& : T -> U) : U | Nil forall U max_of?, min(count : Int) : Array(T)
min : T min, min? : T | Nil min?, min_by(& : T -> U) : T forall U min_by, min_by?(& : T -> U) : T | Nil forall U min_by?, min_of(& : T -> U) : U forall U min_of, min_of?(& : T -> U) : U | Nil forall U min_of?, minmax : Tuple(T, T) minmax, minmax? : Tuple(T | Nil, T | Nil) minmax?, minmax_by(& : T -> U) : Tuple(T, T) forall U minmax_by, minmax_by?(& : T -> U) : Tuple(T, T) | Tuple(Nil, Nil) forall U minmax_by?, minmax_of(& : T -> U) : Tuple(U, U) forall U minmax_of, minmax_of?(& : T -> U) : Tuple(U, U) | Tuple(Nil, Nil) forall U minmax_of?, none?(& : T -> ) : Bool
none?(pattern) : Bool
none? : Bool none?, one?(& : T -> ) : Bool
one?(pattern) : Bool
one? : Bool one?, partition(& : T -> ) : Tuple(Array(T), Array(T))
partition(type : U.class) forall U partition, present? : Bool present?, product(initial : Number)
product
product(initial : Number, & : T -> )
product(& : T -> _) product, reduce(memo, &)
reduce(&) reduce, reduce?(&) reduce?, reject(& : T -> )
reject(type : U.class) forall U
reject(pattern) : Array(T) reject, sample(n : Int, random : Random | Nil = nil) : Array(T)
sample(random : Random | Nil = nil) : T sample, select(& : T -> )
select(type : U.class) : Array(U) forall U
select(pattern) : Array(T) select, size : Int32 size, skip(count : Int) skip, skip_while(& : T -> ) : Array(T) skip_while, sum(initial)
sum
sum(initial, & : T -> )
sum(& : T -> ) sum, take_while(& : T -> ) : Array(T) take_while, tally(hash)
tally : Hash(T, Int32) tally, tally_by(hash, &)
tally_by(&block : T -> U) : Hash(U, Int32) forall U tally_by, to_a : Array(T)
to_a(& : T -> U) : Array(U) forall U to_a, to_h
to_h(& : T -> Tuple(K, V)) forall K, V to_h, to_set : Set(T)
to_set(&block : T -> U) : Set(U) forall U to_set, zip(*others : Indexable | Iterable | Iterator, &)
zip(*others : Indexable | Iterable | Iterator) zip, zip?(*others : Indexable | Iterable | Iterator, &)
zip?(*others : Indexable | Iterable | Iterator) zip?

Class methods inherited from module Enumerable(T)

element_type(x) element_type

Instance methods inherited from struct Struct

==(other : YAML::Any)
==(other) : Bool ==, hash(hasher) hash, inspect(io : IO) : Nil inspect, pretty_print(pp) : Nil pretty_print, to_s(io : IO) : Nil to_s

Class methods inherited from struct Struct

pre_initialize(address : Pointer) : Nil pre_initialize

Instance methods inherited from struct Value

==(other : Log::Metadata::Value)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup

Instance methods inherited from class Object

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io : String | IO, root : String)
from_json(string_or_io : String | IO) from_json, from_yaml(string_or_io : String | IO) from_yaml

Macros inherited from class Object

class_getter(*names, &block) class_getter, class_getter!(*names) class_getter!, class_getter?(*names, &block) class_getter?, class_property(*names, &block) class_property, class_property!(*names) class_property!, class_property?(*names, &block) class_property?, class_setter(*names) class_setter, def_clone def_clone, def_equals(*fields) def_equals, def_equals_and_hash(*fields) def_equals_and_hash, def_hash(*fields) def_hash, delegate(*methods, to object) delegate, forward_missing_to(delegate) forward_missing_to, getter(*names, &block) getter, getter!(*names) getter!, getter?(*names, &block) getter?, property(*names, &block) property, property!(*names) property!, property?(*names, &block) property?, setter(*names) setter

Constructor Detail

def self.additive_identity : self #

Returns the additive identity of this type.

This is an empty set.


def self.new(ctx : YAML::ParseContext, node : YAML::Nodes::Node) #

def self.new(other : Indexable(T)) #

Optimized version of.new used whenother is also anIndexable


def self.new(enumerable : Enumerable(T)) #

Creates a new set from the elements inenumerable.

a = [1, 3, 5]
s = Set.new a
s.empty? # => false

def self.new(pull : JSON::PullParser) #

def self.new(initial_capacity = nil) #

Creates a new, emptySet.

s = Set(Int32).new
s.empty? # => true

An initial capacity can be specified, and it will be set as the initial capacity of the internalHash.


def self.new(ctx : YAML::ParseContext, node : YAML::Nodes::Node, &) #

Instance Method Detail

def &(other : Set) : Set(T) #

Intersection: returns a new set containing elements common to both sets.

Set{1, 1, 3, 5} & Set{1, 2, 3}               # => Set{1, 3}
Set{'a', 'b', 'b', 'z'} & Set{'a', 'b', 'c'} # => Set{'a', 'b'}

def +(other : Set(U)) : Set(T | U) forall U #

Addition: returns a new set containing the unique elements from both sets.

Set{1, 1, 2, 3} + Set{3, 4, 5} # => Set{1, 2, 3, 4, 5}

def -(other : Set) : Set(T) #

Difference: returns a new set containing elements in this set that are not present in the other.

Set{1, 2, 3, 4, 5} - Set{2, 4}               # => Set{1, 3, 5}
Set{'a', 'b', 'b', 'z'} - Set{'a', 'b', 'c'} # => Set{'z'}

def -(other : Enumerable) : Set(T) #

Difference: returns a new set containing elements in this set that are not present in the other enumerable.

Set{1, 2, 3, 4, 5} - [2, 4]               # => Set{1, 3, 5}
Set{'a', 'b', 'b', 'z'} - ['a', 'b', 'c'] # => Set{'z'}

def <<(object : T) : self #

Alias for#add


def ==(other : Set) : Bool #

Returnstrue if both sets have the same elements.

Set{1, 5} == Set{1, 5} # => true

def ===(object : T) : Bool #

Same as#includes?.

It is for convenience with using oncase statement.

red_like = Set{"red", "pink", "violet"}
blue_like = Set{"blue", "azure", "violet"}

case "violet"
when red_like & blue_like
  puts "red & blue like color!"
when red_like
  puts "red like color!"
when blue_like
  puts "blue like color!"
end

See also:Object#===.


def ^(other : Set(U)) : Set(T | U) forall U #

Symmetric Difference: returns a new set(self - other) | (other - self). Equivalently, returns(self | other) - (self & other).

Set{1, 2, 3, 4, 5} ^ Set{2, 4, 6}            # => Set{1, 3, 5, 6}
Set{'a', 'b', 'b', 'z'} ^ Set{'a', 'b', 'c'} # => Set{'z', 'c'}

def ^(other : Enumerable(U)) : Set(T | U) forall U #

Symmetric Difference: returns a new set(self - other) | (other - self). Equivalently, returns(self | other) - (self & other).

Set{1, 2, 3, 4, 5} ^ [2, 4, 6]            # => Set{1, 3, 5, 6}
Set{'a', 'b', 'b', 'z'} ^ ['a', 'b', 'c'] # => Set{'z', 'c'}

def |(other : Set(U)) : Set(T | U) forall U #

Union: returns a new set containing all unique elements from both sets.

Set{1, 1, 3, 5} | Set{1, 2, 3}               # => Set{1, 3, 5, 2}
Set{'a', 'b', 'b', 'z'} | Set{'a', 'b', 'c'} # => Set{'a', 'b', 'z', 'c'}

See also:#concat to add elements from a set toself.


def add(object : T) : self #

Addsobject to the set and returnsself.

s = Set{1, 5}
s.includes? 8 # => false
s.add(8)
s.includes? 8 # => true

def add?(object : T) : Bool #

Addsobject to the set and returnstrue on success andfalse if the value was already in the set.

s = Set{1, 5}
s.add? 8 # => true
s.add? 8 # => false

def clear : self #

Removes all elements in the set, and returnsself.

s = Set{1, 5}
s.size # => 2
s.clear
s.size # => 0

def clone : Set(T) #

Returns a newSet with all of the elements cloned.


def compare_by_identity : self #

Makes this set compare objects using their object identity (object_id) for types that define such method (Reference types, but also structs that might wrap otherReference types and delegate theobject_id method to them).

s = Set{"foo", "bar"}
s.includes?("fo" + "o") # => true

s.compare_by_identity
s.compare_by_identity?  # => true
s.includes?("fo" + "o") # => false # not the same String instance

def compare_by_identity? : Bool #

Returnstrue if this Set is comparing objects byobject_id.

See#compare_by_identity.


def concat(elems) : self #

Adds#each element ofelems to the set and returnsself.

s = Set{1, 5}
s.concat [5, 5, 8, 9]
s.size # => 4

See also:#| to merge two sets and return a new one.


def delete(object) : Bool #

Removes theobject from the set and returnstrue if it was present, otherwise returnsfalse.

s = Set{1, 5}
s.includes? 5 # => true
s.delete 5    # => true
s.includes? 5 # => false
s.delete 5    # => false

def dup : Set(T) #

Returns a newSet with all of the same elements.


def each(& : T -> ) : Nil #

Yields each element of the set, and returnsnil.


def each #

Returns an iterator for each element of the set.


def empty? : Bool #

Returnstrue if the set is empty.

s = Set(Int32).new
s.empty? # => true
s << 3
s.empty? # => false

def hash(hasher) #

SeeObject#hash(hasher)


def includes?(object) : Bool #

Returnstrue ifobject exists in the set.

s = Set{1, 5}
s.includes? 5 # => true
s.includes? 9 # => false

def inspect(io : IO) : Nil #

Alias of#to_s.


def intersects?(other : Set) : Bool #

Returnstrue if the set and the given set have at least one element in common.

Set{1, 2, 3}.intersects? Set{4, 5} # => false
Set{1, 2, 3}.intersects? Set{3, 4} # => true

def map!(& : T -> T) : self #

Replaces every element of the set with a value returned from the block, and returnsself.


def pretty_print(pp) : Nil #

def proper_subset_of?(other : Set) : Bool #

Returnstrue if the set is a proper subset of theother set.

This set must have fewer elements than theother set, and all of elements in this set must be present in theother set.

Set{1, 5}.proper_subset_of? Set{1, 3, 5}    # => true
Set{1, 3, 5}.proper_subset_of? Set{1, 3, 5} # => false

def proper_superset_of?(other : Set) : Bool #

Returnstrue if the set is a superset of theother set.

Theother must have fewer elements than this set, and all of elements in theother set must be present in this set.

Set{1, 3, 5}.proper_superset_of? Set{1, 5}    # => true
Set{1, 3, 5}.proper_superset_of? Set{1, 3, 5} # => false

def rehash : Nil #

Rebuilds the set based on the current elements.

When using mutable data types as elements, modifying an elements after it was inserted into theSet may lead to undefined behaviour. This method re-indexes the set using the current elements.


def reject!(& : T -> ) : self #

Deletes every element of the set for which the block is truthy, and returns self.


def select!(& : T -> ) : self #

Deletes every element of the set for which the block is falsey, and returns self.


def size : Int32 #

Returns the number of elements in the set.

s = Set{1, 5}
s.size # => 2

def subset_of?(other : Set) : Bool #

Returnstrue if the set is a subset of theother set.

This set must have the same or fewer elements than theother set, and all of elements in this set must be present in theother set.

Set{1, 5}.subset_of? Set{1, 3, 5}    # => true
Set{1, 3, 5}.subset_of? Set{1, 3, 5} # => true

def subtract(other : Enumerable) : self #

Returnsself after removing from it those elements that are present in the given enumerable.

Set{'a', 'b', 'b', 'z'}.subtract Set{'a', 'b', 'c'} # => Set{'z'}
Set{1, 2, 3, 4, 5}.subtract [2, 4, 6]               # => Set{1, 3, 5}

def superset_of?(other : Set) : Bool #

Returnstrue if the set is a superset of theother set.

Theother must have the same or fewer elements than this set, and all of elements in theother set must be present in this set.

Set{1, 3, 5}.superset_of? Set{1, 5}    # => true
Set{1, 3, 5}.superset_of? Set{1, 3, 5} # => true

def to_a : Array(T) #

Returns the elements as anArray.

Set{1, 5}.to_a # => [1,5]

def to_a(& : T -> U) : Array(U) forall U #

Returns anArray with the results of runningblock against each element of the collection.

Set{1, 2, 3, 4, 5}.to_a { |i| i // 2 } # => [0, 1, 1, 2, 2]

def to_json(json : JSON::Builder) : Nil #

def to_s(io : IO) : Nil #

Writes a string representation of the set toio.


def to_yaml(yaml : YAML::Nodes::Builder) : Nil #