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Object
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.
The equality of each couple of elements is determined according to Object#eql? and Object#hash, since Set uses Hash as storage.
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.
The comparison operators <, >, <= and >= are implemented as shorthand for the {proper_,}{subset?,superset?} methods. However, the <=> operator is intentionally left out because not every pair of sets is comparable. ({x,y} vs. {x,z} for example)
require 'set' s1 = Set.new [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: {6, 1, 2, "foo"}> s1.subset? s2 # -> false s2.subset? s1 # -> true
- Akinori MUSHA <knu@iDaemons.org> (current maintainer)
Creates a new set containing the given objects.
# File set.rb, line 64 def self.[](*ary) new(ary) 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.
# File set.rb, line 73 def initialize(enum = nil, &block) # :yields: o @hash ||= Hash.new enum.nil? and return if block do_with_enum(enum) { |o| add(block[o]) } else merge(enum) end end
Returns a new set containing elements common to the set and the given enumerable object.
# File set.rb, line 350 def &(enum) n = self.class.new do_with_enum(enum) { |o| n.add(o) if include?(o) } n end
Returns a new set built by duplicating the set, removing every element that appears in the given enumerable object.
# File set.rb, line 343 def -(enum) dup.subtract(enum) end
Returns true if two sets are equal. The equality of each couple of elements is defined according to Object#eql?.
# File set.rb, line 368 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 a new set containing elements exclusive between the set and the given enumerable object. (set ^ enum) is equivalent to ((set | enum) - (set & enum)).
# File set.rb, line 360 def ^(enum) n = Set.new(enum) each { |o| if n.include?(o) then n.delete(o) else n.add(o) end } n end
Adds the given object to the set and returns self. Use merge
to add many elements at once.
# File set.rb, line 238 def add(o) @hash[o] = true self end
Adds the given object to the set and returns self. If the object is already in the set, returns nil.
# File set.rb, line 246 def add?(o) if include?(o) nil else add(o) end 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.
e.g.:
require 'set' files = Set.new(Dir.glob("*.rb")) hash = files.classify { |f| File.mtime(f).year } p hash # => {2000=>#<Set: {"a.rb", "b.rb"}>, # 2001=>#<Set: {"c.rb", "d.rb", "e.rb"}>, # 2002=>#<Set: {"f.rb"}>}
# File set.rb, line 402 def classify # :yields: o block_given? or return enum_for(__method__) h = {} each { |i| x = yield(i) (h[x] ||= self.class.new).add(i) } h end
Removes all elements and returns self.
# File set.rb, line 131 def clear @hash.clear self end
Replaces the elements with ones returned by collect().
# File set.rb, line 288 def collect! block_given? or return enum_for(__method__) set = self.class.new each { |o| set << yield(o) } replace(set) end
Deletes the given object from the set and returns self. Use
subtract
to delete many items at once.
# File set.rb, line 256 def delete(o) @hash.delete(o) self end
Deletes the given object from the set and returns self. If the object is not in the set, returns nil.
# File set.rb, line 263 def delete?(o) if include?(o) delete(o) else nil end end
Deletes every element of the set for which block evaluates to true, and returns self.
# File set.rb, line 273 def delete_if block_given? or return enum_for(__method__) to_a.each { |o| @hash.delete(o) if yield(o) } self 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).
e.g.:
require 'set' numbers = Set[1, 3, 4, 6, 9, 10, 11] set = numbers.divide { |i,j| (i - j).abs == 1 } p set # => #<Set: {#<Set: {1}>, # #<Set: {11, 9, 10}>, # #<Set: {3, 4}>, # #<Set: {6}>}>
# File set.rb, line 431 def divide(&func) func or return enum_for(__method__) 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
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 set.rb, line 230 def each(&block) block or return enum_for(__method__) @hash.each_key(&block) self end
Returns true if the set contains no elements.
# File set.rb, line 126 def empty? @hash.empty? end
Returns a new set that is a copy of the set, flattening each containing set recursively.
# File set.rb, line 175 def flatten self.class.new.flatten_merge(self) end
Equivalent to #flatten, but replaces the receiver with the result in place. Returns nil if no modifications were made.
# File set.rb, line 181 def flatten! if detect { |e| e.is_a?(Set) } replace(flatten()) else nil end end
Returns true if the set contains the given object.
# File set.rb, line 190 def include?(o) @hash.include?(o) end
Copy internal hash.
# File set.rb, line 97 def initialize_copy(orig) @hash = orig.instance_variable_get(:@hash).dup end
Returns a string containing a human-readable representation of the set. (“#<Set: {element1, element2, …}>”)
# File set.rb, line 465 def inspect ids = (Thread.current[InspectKey] ||= []) if ids.include?(object_id) return sprintf('#<%s: {...}>', self.class.name) end begin ids << object_id return sprintf('#<%s: {%s}>', self.class, to_a.inspect[1..-2]) ensure ids.pop end end
Deletes every element of the set for which block evaluates to false, and returns self.
# File set.rb, line 281 def keep_if block_given? or return enum_for(__method__) to_a.each { |o| @hash.delete(o) unless yield(o) } self end
Merges the elements of the given enumerable object to the set and returns self.
# File set.rb, line 316 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
Returns true if the set is a proper subset of the given set.
# File set.rb, line 220 def proper_subset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if set.size <= size all? { |o| set.include?(o) } end
Returns true if the set is a proper superset of the given set.
# File set.rb, line 204 def proper_superset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if size <= set.size set.all? { |o| include?(o) } end
Equivalent to #delete_if, but returns nil if no changes were made.
# File set.rb, line 298 def reject!(&block) block or return enum_for(__method__) n = size delete_if(&block) size == n ? nil : self end
Replaces the contents of the set with the contents of the given enumerable object and returns self.
# File set.rb, line 138 def replace(enum) if enum.instance_of?(self.class) @hash.replace(enum.instance_variable_get(:@hash)) else clear merge(enum) end self end
Equivalent to #keep_if, but returns nil if no changes were made.
# File set.rb, line 307 def select!(&block) block or return enum_for(__method__) n = size keep_if(&block) size == n ? nil : self end
Returns the number of elements.
# File set.rb, line 120 def size @hash.size end
Returns true if the set is a subset of the given set.
# File set.rb, line 212 def subset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if set.size < size all? { |o| set.include?(o) } end
Deletes every element that appears in the given enumerable object and returns self.
# File set.rb, line 328 def subtract(enum) do_with_enum(enum) { |o| delete(o) } self end
Returns true if the set is a superset of the given set.
# File set.rb, line 196 def superset?(set) set.is_a?(Set) or raise ArgumentError, "value must be a set" return false if size < set.size set.all? { |o| include?(o) } end