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 68: def initialize(enum = nil, &block) # :yields: o 69: @hash ||= Hash.new 70: 71: enum.nil? and return 72: 73: if block 74: enum.each { |o| add(block[o]) } 75: else 76: merge(enum) 77: end 78: end
Returns a new set containing elements common to the set and the given enumerable object.
# File lib/set.rb, line 297 297: def &(enum) 298: enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" 299: n = self.class.new 300: enum.each { |o| n.add(o) if include?(o) } 301: n 302: end
Returns true if two sets are equal. The equality of each couple of elements is defined according to Object#eql?.
# File lib/set.rb, line 317 317: def ==(set) 318: equal?(set) and return true 319: 320: set.is_a?(Set) && size == set.size or return false 321: 322: hash = @hash.dup 323: set.all? { |o| hash.include?(o) } 324: 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 308 308: def ^(enum) 309: enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" 310: n = Set.new(enum) 311: each { |o| if n.include?(o) then n.delete(o) else n.add(o) end } 312: n 313: 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 209 209: def add?(o) 210: if include?(o) 211: nil 212: else 213: add(o) 214: end 215: 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 348 348: def classify # :yields: o 349: h = {} 350: 351: each { |i| 352: x = yield(i) 353: (h[x] ||= self.class.new).add(i) 354: } 355: 356: h 357: end
Removes all elements and returns self.
# File lib/set.rb, line 97 97: def clear 98: @hash.clear 99: self 100: end
Do collect() destructively.
# File lib/set.rb, line 242 242: def collect! 243: set = self.class.new 244: each { |o| set << yield(o) } 245: replace(set) 246: 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 226 226: def delete?(o) 227: if include?(o) 228: delete(o) 229: else 230: nil 231: end 232: end
Deletes every element of the set for which block evaluates to true, and returns self.
# File lib/set.rb, line 236 236: def delete_if 237: to_a.each { |o| @hash.delete(o) if yield(o) } 238: self 239: 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 375 375: def divide(&func) 376: if func.arity == 2 377: require 'tsort' 378: 379: class << dig = {} # :nodoc: 380: include TSort 381: 382: alias tsort_each_node each_key 383: def tsort_each_child(node, &block) 384: fetch(node).each(&block) 385: end 386: end 387: 388: each { |u| 389: dig[u] = a = [] 390: each{ |v| func.call(u, v) and a << v } 391: } 392: 393: set = Set.new() 394: dig.each_strongly_connected_component { |css| 395: set.add(self.class.new(css)) 396: } 397: set 398: else 399: Set.new(classify(&func).values) 400: end 401: end
Returns true if the set contains no elements.
# File lib/set.rb, line 92 92: def empty? 93: @hash.empty? 94: 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 148 148: def flatten! 149: if detect { |e| e.is_a?(Set) } 150: replace(flatten()) 151: else 152: nil 153: end 154: end
Returns true if the set contains the given object.
# File lib/set.rb, line 157 157: def include?(o) 158: @hash.include?(o) 159: end
Copy internal hash.
# File lib/set.rb, line 81 81: def initialize_copy(orig) 82: @hash = orig.instance_eval{@hash}.dup 83: end
Returns a string containing a human-readable representation of the set. ("#<Set: {element1, element2, …}>")
# File lib/set.rb, line 407 407: def inspect 408: ids = (Thread.current[InspectKey] ||= []) 409: 410: if ids.include?(object_id) 411: return sprintf('#<%s: {...}>', self.class.name) 412: end 413: 414: begin 415: ids << object_id 416: return sprintf('#<%s: {%s}>', self.class, to_a.inspect[1..-2]) 417: ensure 418: ids.pop 419: end 420: end
Merges the elements of the given enumerable object to the set and returns self.
# File lib/set.rb, line 259 259: def merge(enum) 260: if enum.is_a?(Set) 261: @hash.update(enum.instance_eval { @hash }) 262: else 263: enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" 264: enum.each { |o| add(o) } 265: end 266: 267: self 268: end
Returns true if the set is a proper subset of the given set.
# File lib/set.rb, line 184 184: def proper_subset?(set) 185: set.is_a?(Set) or raise ArgumentError, "value must be a set" 186: return false if set.size <= size 187: all? { |o| set.include?(o) } 188: end
Returns true if the set is a proper superset of the given set.
# File lib/set.rb, line 170 170: def proper_superset?(set) 171: set.is_a?(Set) or raise ArgumentError, "value must be a set" 172: return false if size <= set.size 173: set.all? { |o| include?(o) } 174: end
Equivalent to Set#delete_if, but returns nil if no changes were made.
# File lib/set.rb, line 251 251: def reject! 252: n = size 253: delete_if { |o| yield(o) } 254: size == n ? nil : self 255: end
Replaces the contents of the set with the contents of the given enumerable object and returns self.
# File lib/set.rb, line 104 104: def replace(enum) 105: if enum.class == self.class 106: @hash.replace(enum.instance_eval { @hash }) 107: else 108: enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" 109: clear 110: enum.each { |o| add(o) } 111: end 112: 113: self 114: end
Returns true if the set is a subset of the given set.
# File lib/set.rb, line 177 177: def subset?(set) 178: set.is_a?(Set) or raise ArgumentError, "value must be a set" 179: return false if set.size < size 180: all? { |o| set.include?(o) } 181: end
Deletes every element that appears in the given enumerable object and returns self.
# File lib/set.rb, line 272 272: def subtract(enum) 273: enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable" 274: enum.each { |o| delete(o) } 275: self 276: end
Returns true if the set is a superset of the given set.
# File lib/set.rb, line 163 163: def superset?(set) 164: set.is_a?(Set) or raise ArgumentError, "value must be a set" 165: return false if size < set.size 166: set.all? { |o| include?(o) } 167: end
Converts the set to an array. The order of elements is uncertain.
# File lib/set.rb, line 117 117: def to_a 118: @hash.keys 119: end
# File lib/set.rb, line 121 121: def flatten_merge(set, seen = Set.new) 122: set.each { |e| 123: if e.is_a?(Set) 124: if seen.include?(e_id = e.object_id) 125: raise ArgumentError, "tried to flatten recursive Set" 126: end 127: 128: seen.add(e_id) 129: flatten_merge(e, seen) 130: seen.delete(e_id) 131: else 132: add(e) 133: end 134: } 135: 136: self 137: end