Class | Set |
In: |
lib/set.rb
|
Parent: | 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.
Several methods accept any Enumerable object (implementing each) for greater flexibility: new, replace, merge, subtract, |, &, -, ^.
The equality of each couple of elements is determined according to Object#eql? and Object#hash, since Set uses Hash as storage.
Finally, if you are using class Set, you can also use Enumerable#to_set for convenience.
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 elements of the given enumerable object.
If a block is given, the elements of enum are preprocessed by the given block.
# File lib/set.rb, line 68 def initialize(enum = nil, &block) # :yields: o @hash ||= Hash.new enum.nil? and return if block enum.each { |o| add(block[o]) } else merge(enum) 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 lib/set.rb, line 308 def ^(enum) enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" 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. If the object is already in the set, returns nil.
# File lib/set.rb, line 209 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 lib/set.rb, line 348 def classify # :yields: o h = {} each { |i| x = yield(i) (h[x] ||= self.class.new).add(i) } h end
Do collect() destructively.
# File lib/set.rb, line 242 def collect! set = self.class.new each { |o| set << yield(o) } replace(set) 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 226 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 lib/set.rb, line 236 def delete_if 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 lib/set.rb, line 375 def divide(&func) 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
Returns true if the set contains no elements.
# File lib/set.rb, line 92 def empty? @hash.empty? 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 148 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 lib/set.rb, line 157 def include?(o) @hash.include?(o) end
Copy internal hash.
# File lib/set.rb, line 81 def initialize_copy(orig) @hash = orig.instance_eval{@hash}.dup end
Returns a string containing a human-readable representation of the set. ("#<Set: {element1, element2, …}>")
# File lib/set.rb, line 407 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
Merges the elements of the given enumerable object to the set and returns self.
# File lib/set.rb, line 259 def merge(enum) if enum.is_a?(Set) @hash.update(enum.instance_eval { @hash }) else enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" enum.each { |o| add(o) } end self end
Returns true if the set is a proper subset of the given set.
# File lib/set.rb, line 184 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 lib/set.rb, line 170 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 Set#delete_if, but returns nil if no changes were made.
# File lib/set.rb, line 251 def reject! n = size delete_if { |o| yield(o) } size == n ? nil : self end
Replaces the contents of the set with the contents of the given enumerable object and returns self.
# File lib/set.rb, line 104 def replace(enum) if enum.class == self.class @hash.replace(enum.instance_eval { @hash }) else enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" clear enum.each { |o| add(o) } end self end
Returns true if the set is a subset of the given set.
# File lib/set.rb, line 177 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 lib/set.rb, line 272 def subtract(enum) enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" enum.each { |o| delete(o) } self end
Returns true if the set is a superset of the given set.
# File lib/set.rb, line 163 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
Converts the set to an array. The order of elements is uncertain.
# File lib/set.rb, line 117 def to_a @hash.keys end