| 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