This library provides the Set class, which deals with a collection of unordered values with no duplicates. It is a hybrid of Array's intuitive inter-operation facilities and Hash's fast lookup.
The method to_set is added to Enumerable for convenience.
Set implements a collection of unordered values with no duplicates. This is a hybrid of Array's intuitive inter-operation facilities and Hash's fast lookup.
Set is easy to use with Enumerable objects (implementing each). Most of the initializer methods and binary operators accept generic Enumerable objects besides sets and arrays. An Enumerable object can be converted to Set using the to_set method.
Set uses Hash as storage, so you must note the following points:
Equality of elements is determined according to Object#eql? and Object#hash. Use Set#compare_by_identity to make a set compare its elements by their identity.
Set assumes that the identity of each element does not change while it is stored. Modifying an element of a set will render the set to an unreliable state.
When a string is to be stored, a frozen copy of the string is stored instead unless the original string is already frozen.
The comparison operators <, >, <=, and >= are implemented as shorthand for the {proper_,}{subset?,superset?} methods. The <=> operator reflects this order, or return nil for sets that both have distinct elements ({x, y} vs. {x, z} for example).
require 'set'
s1 = Set[1, 2] #=> #<Set: {1, 2}>
s2 = [1, 2].to_set #=> #<Set: {1, 2}>
s1 == s2 #=> true
s1.add("foo") #=> #<Set: {1, 2, "foo"}>
s1.merge([2, 6]) #=> #<Set: {1, 2, "foo", 6}>
s1.subset?(s2) #=> false
s2.subset?(s1) #=> true
Akinori MUSHA <[email protected]> (current maintainer)
# File lib/set.rb, line 73 def self.[](*ary) new(ary) end
Creates a new set containing the given objects.
Set[1, 2] # => #<Set: {1, 2}>
Set[1, 2, 1] # => #<Set: {1, 2}>
Set[1, 'c', :s] # => #<Set: {1, "c", :s}>
# File lib/set.rb, line 88
def initialize(enum = nil, &block) # :yields: o
@hash ||= Hash.new(false)
enum.nil? and return
if block
do_with_enum(enum) { |o| add(block[o]) }
else
merge(enum)
end
end Creates a new set containing the elements of the given enumerable object.
If a block is given, the elements of enum are preprocessed by the given block.
Set.new([1, 2]) #=> #<Set: {1, 2}>
Set.new([1, 2, 1]) #=> #<Set: {1, 2}>
Set.new([1, 'c', :s]) #=> #<Set: {1, "c", :s}>
Set.new(1..5) #=> #<Set: {1, 2, 3, 4, 5}>
Set.new([1, 2, 3]) { |x| x * x } #=> #<Set: {1, 4, 9}>
# File lib/set.rb, line 481
def &(enum)
n = self.class.new
if enum.is_a?(Set)
if enum.size > size
each { |o| n.add(o) if enum.include?(o) }
else
enum.each { |o| n.add(o) if include?(o) }
end
else
do_with_enum(enum) { |o| n.add(o) if include?(o) }
end
n
end Returns a new set containing elements common to the set and the given enumerable object.
Set[1, 3, 5] & Set[3, 2, 1] #=> #<Set: {3, 1}>
Set['a', 'b', 'z'] & ['a', 'b', 'c'] #=> #<Set: {"a", "b"}>
# File lib/set.rb, line 471 def -(enum) dup.subtract(enum) end
Returns a new set built by duplicating the set, removing every element that appears in the given enumerable object.
Set[1, 3, 5] - Set[1, 5] #=> #<Set: {3}>
Set['a', 'b', 'z'] - ['a', 'c'] #=> #<Set: {"b", "z"}>
# File lib/set.rb, line 306 def <=>(set) return unless set.is_a?(Set) case size <=> set.size when -1 then -1 if proper_subset?(set) when +1 then +1 if proper_superset?(set) else 0 if self.==(set) end end
Returns 0 if the set are equal, -1 / +1 if the set is a proper subset / superset of the given set, or nil if they both have unique elements.
# File lib/set.rb, line 515
def ==(other)
if self.equal?(other)
true
elsif other.instance_of?(self.class)
@hash == other.instance_variable_get(:@hash)
elsif other.is_a?(Set) && self.size == other.size
other.all? { |o| @hash.include?(o) }
else
false
end
end Returns true if two sets are equal. The equality of each couple of elements is defined according to Object#eql?.
Set[1, 2] == Set[2, 1] #=> true Set[1, 3, 5] == Set[1, 5] #=> false Set['a', 'b', 'c'] == Set['a', 'c', 'b'] #=> true Set['a', 'b', 'c'] == ['a', 'c', 'b'] #=> false
Returns true if the given object is a member of the set, and false otherwise.
Used in case statements:
require 'set' case :apple when Set[:potato, :carrot] "vegetable" when Set[:apple, :banana] "fruit" end # => "fruit"
Or by itself:
Set[1, 2, 3] === 2 #=> true Set[1, 2, 3] === 4 #=> false
# File lib/set.rb, line 502
def ^(enum)
n = Set.new(enum)
each { |o| n.add(o) unless n.delete?(o) }
n
end Returns a new set containing elements exclusive between the set and the given enumerable object. (set ^ enum) is equivalent to ((set | enum) - (set & enum)).
Set[1, 2] ^ Set[2, 3] #=> #<Set: {3, 1}>
Set[1, 'b', 'c'] ^ ['b', 'd'] #=> #<Set: {"d", 1, "c"}>
# File lib/set.rb, line 354 def add(o) @hash[o] = true self end
Adds the given object to the set and returns self. Use merge to add many elements at once.
Set[1, 2].add(3) #=> #<Set: {1, 2, 3}>
Set[1, 2].add([3, 4]) #=> #<Set: {1, 2, [3, 4]}>
Set[1, 2].add(2) #=> #<Set: {1, 2}>
# File lib/set.rb, line 366 def add?(o) add(o) unless include?(o) end
Adds the given object to the set and returns self. If the object is already in the set, returns nil.
Set[1, 2].add?(3) #=> #<Set: {1, 2, 3}>
Set[1, 2].add?([3, 4]) #=> #<Set: {1, 2, [3, 4]}>
Set[1, 2].add?(2) #=> nil
# File lib/set.rb, line 584
def classify # :yields: o
block_given? or return enum_for(__method__) { size }
h = {}
each { |i|
(h[yield(i)] ||= self.class.new).add(i)
}
h
end Classifies the set by the return value of the given block and returns a hash of {value => set of elements} pairs. The block is called once for each element of the set, passing the element as parameter.
require 'set'
files = Set.new(Dir.glob("*.rb"))
hash = files.classify { |f| File.mtime(f).year }
hash #=> {2000=>#<Set: {"a.rb", "b.rb"}>,
# 2001=>#<Set: {"c.rb", "d.rb", "e.rb"}>,
# 2002=>#<Set: {"f.rb"}>}
Returns an enumerator if no block is given.
# File lib/set.rb, line 169 def clear @hash.clear self end
Removes all elements and returns self.
set = Set[1, 'c', :s] #=> #<Set: {1, "c", :s}>
set.clear #=> #<Set: {}>
set #=> #<Set: {}>
# File lib/set.rb, line 407
def collect!
block_given? or return enum_for(__method__) { size }
set = self.class.new
each { |o| set << yield(o) }
replace(set)
end Replaces the elements with ones returned by collect(). Returns an enumerator if no block is given.
# File lib/set.rb, line 102
def compare_by_identity
if @hash.respond_to?(:compare_by_identity)
@hash.compare_by_identity
self
else
raise NotImplementedError, "#{self.class.name}\##{__method__} is not implemented"
end
end Makes the set compare its elements by their identity and returns self. This method may not be supported by all subclasses of Set.
# File lib/set.rb, line 113 def compare_by_identity? @hash.respond_to?(:compare_by_identity?) && @hash.compare_by_identity? end
Returns true if the set will compare its elements by their identity. Also see Set#compare_by_identity.
# File lib/set.rb, line 372 def delete(o) @hash.delete(o) self end
Deletes the given object from the set and returns self. Use subtract to delete many items at once.
# File lib/set.rb, line 379 def delete?(o) delete(o) if include?(o) end
Deletes the given object from the set and returns self. If the object is not in the set, returns nil.
# File lib/set.rb, line 386
def delete_if
block_given? or return enum_for(__method__) { size }
# @hash.delete_if should be faster, but using it breaks the order
# of enumeration in subclasses.
select { |o| yield o }.each { |o| @hash.delete(o) }
self
end Deletes every element of the set for which block evaluates to true, and returns self. Returns an enumerator if no block is given.
# File lib/set.rb, line 335 def disjoint?(set) !intersect?(set) end
Returns true if the set and the given set have no element in common. This method is the opposite of intersect?.
Set[1, 2, 3].disjoint? Set[3, 4] #=> false Set[1, 2, 3].disjoint? Set[4, 5] #=> true
# File lib/set.rb, line 612
def divide(&func)
func or return enum_for(__method__) { size }
if func.arity == 2
require 'tsort'
class << dig = {} # :nodoc:
include TSort
alias tsort_each_node each_key
def tsort_each_child(node, &block)
fetch(node).each(&block)
end
end
each { |u|
dig[u] = a = []
each{ |v| func.call(u, v) and a << v }
}
set = Set.new()
dig.each_strongly_connected_component { |css|
set.add(self.class.new(css))
}
set
else
Set.new(classify(&func).values)
end
end Divides the set into a set of subsets according to the commonality defined by the given block.
If the arity of the block is 2, elements o1 and o2 are in common if block.call(o1, o2) is true. Otherwise, elements o1 and o2 are in common if block.call(o1) == block.call(o2).
require 'set'
numbers = Set[1, 3, 4, 6, 9, 10, 11]
set = numbers.divide { |i,j| (i - j).abs == 1 }
set #=> #<Set: {#<Set: {1}>,
# #<Set: {11, 9, 10}>,
# #<Set: {3, 4}>,
# #<Set: {6}>}>
Returns an enumerator if no block is given.
# File lib/set.rb, line 342
def each(&block)
block or return enum_for(__method__) { size }
@hash.each_key(&block)
self
end Calls the given block once for each element in the set, passing the element as parameter. Returns an enumerator if no block is given.
# File lib/set.rb, line 160 def empty? @hash.empty? end
Returns true if the set contains no elements.
# File lib/set.rb, line 230 def flatten self.class.new.flatten_merge(self) end
Returns a new set that is a copy of the set, flattening each containing set recursively.
# File lib/set.rb, line 236
def flatten!
replace(flatten()) if any? { |e| e.is_a?(Set) }
end Equivalent to Set#flatten, but replaces the receiver with the result in place. Returns nil if no modifications were made.
# File lib/set.rb, line 246 def include?(o) @hash[o] end
Returns true if the set contains the given object.
Note that include? and member? do not test member equality using == as do other Enumerables.
See also Enumerable#include?
# File lib/set.rb, line 136 def initialize_clone(orig, **options) super @hash = orig.instance_variable_get(:@hash).clone(**options) end
Clone internal hash.
# File lib/set.rb, line 129 def initialize_dup(orig) super @hash = orig.instance_variable_get(:@hash).dup end
Dup internal hash.
# File lib/set.rb, line 652
def inspect
ids = (Thread.current[InspectKey] ||= [])
if ids.include?(object_id)
return sprintf('#<%s: {...}>', self.class.name)
end
ids << object_id
begin
return sprintf('#<%s: {%s}>', self.class, to_a.inspect[1..-2])
ensure
ids.pop
end
end Returns a string containing a human-readable representation of the set (“#<Set: {element1, element2, …}>”).
# File lib/set.rb, line 321
def intersect?(set)
set.is_a?(Set) or raise ArgumentError, "value must be a set"
if size < set.size
any? { |o| set.include?(o) }
else
set.any? { |o| include?(o) }
end
end Returns true if the set and the given set have at least one element in common.
Set[1, 2, 3].intersect? Set[4, 5] #=> false Set[1, 2, 3].intersect? Set[3, 4] #=> true
# File lib/set.rb, line 644 def join(separator=nil) to_a.join(separator) end
Returns a string created by converting each element of the set to a string See also: Array#join
# File lib/set.rb, line 397
def keep_if
block_given? or return enum_for(__method__) { size }
# @hash.keep_if should be faster, but using it breaks the order of
# enumeration in subclasses.
reject { |o| yield o }.each { |o| @hash.delete(o) }
self
end Deletes every element of the set for which block evaluates to false, and returns self. Returns an enumerator if no block is given.
# File lib/set.rb, line 438
def merge(enum)
if enum.instance_of?(self.class)
@hash.update(enum.instance_variable_get(:@hash))
else
do_with_enum(enum) { |o| add(o) }
end
self
end Merges the elements of the given enumerable object to the set and returns self.
# File lib/set.rb, line 291
def proper_subset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:<)
@hash < set.instance_variable_get(:@hash)
when set.is_a?(Set)
size < set.size && all? { |o| set.include?(o) }
else
raise ArgumentError, "value must be a set"
end
end Returns true if the set is a proper subset of the given set.
# File lib/set.rb, line 265
def proper_superset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:>)
@hash > set.instance_variable_get(:@hash)
when set.is_a?(Set)
size > set.size && set.all? { |o| include?(o) }
else
raise ArgumentError, "value must be a set"
end
end Returns true if the set is a proper superset of the given set.
# File lib/set.rb, line 417
def reject!(&block)
block or return enum_for(__method__) { size }
n = size
delete_if(&block)
self if size != n
end Equivalent to Set#delete_if, but returns nil if no changes were made. Returns an enumerator if no block is given.
# File lib/set.rb, line 180
def replace(enum)
if enum.instance_of?(self.class)
@hash.replace(enum.instance_variable_get(:@hash))
self
else
do_with_enum(enum) # make sure enum is enumerable before calling clear
clear
merge(enum)
end
end Replaces the contents of the set with the contents of the given enumerable object and returns self.
set = Set[1, 'c', :s] #=> #<Set: {1, "c", :s}>
set.replace([1, 2]) #=> #<Set: {1, 2}>
set #=> #<Set: {1, 2}>
# File lib/set.rb, line 540
def reset
if @hash.respond_to?(:rehash)
@hash.rehash # This should perform frozenness check.
else
raise FrozenError, "can't modify frozen #{self.class.name}" if frozen?
end
self
end Resets the internal state after modification to existing elements and returns self.
Elements will be reindexed and deduplicated.
# File lib/set.rb, line 426
def select!(&block)
block or return enum_for(__method__) { size }
n = size
keep_if(&block)
self if size != n
end Equivalent to Set#keep_if, but returns nil if no changes were made. Returns an enumerator if no block is given.
# File lib/set.rb, line 154 def size @hash.size end
Returns the number of elements.
# File lib/set.rb, line 278
def subset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:<=)
@hash <= set.instance_variable_get(:@hash)
when set.is_a?(Set)
size <= set.size && all? { |o| set.include?(o) }
else
raise ArgumentError, "value must be a set"
end
end Returns true if the set is a subset of the given set.
# File lib/set.rb, line 450
def subtract(enum)
do_with_enum(enum) { |o| delete(o) }
self
end Deletes every element that appears in the given enumerable object and returns self.
# File lib/set.rb, line 252
def superset?(set)
case
when set.instance_of?(self.class) && @hash.respond_to?(:>=)
@hash >= set.instance_variable_get(:@hash)
when set.is_a?(Set)
size >= set.size && set.all? { |o| include?(o) }
else
raise ArgumentError, "value must be a set"
end
end Returns true if the set is a superset of the given set.
# File lib/set.rb, line 195 def to_a @hash.keys end
Converts the set to an array. The order of elements is uncertain.
Set[1, 2].to_a #=> [1, 2] Set[1, 'c', :s].to_a #=> [1, "c", :s]
# File ext/json/lib/json/add/set.rb, line 25 def to_json(*args) as_json.to_json(*args) end
return the JSON value
# File lib/set.rb, line 204 def to_set(klass = Set, *args, &block) return self if instance_of?(Set) && klass == Set && block.nil? && args.empty? klass.new(self, *args, &block) end
Returns self if no arguments are given. Otherwise, converts the set to another with klass.new(self, *args, &block).
In subclasses, returns klass.new(self, *args, &block) unless overridden.
# File lib/set.rb, line 460 def |(enum) dup.merge(enum) end
Returns a new set built by merging the set and the elements of the given enumerable object.
Set[1, 2, 3] | Set[2, 4, 5] #=> #<Set: {1, 2, 3, 4, 5}>
Set[1, 5, 'z'] | (1..6) #=> #<Set: {1, 5, "z", 2, 3, 4, 6}>
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Licensed under the Ruby License.
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