ruby array中找出重复元素
ruby array中找出重复元素Ruby代码1.#上文的inject现在用上了
2.module Enumerable
3.def dups
4. inject({}) {|h,v| h=h.to_i+1; h}.reject{|k,v| v==1}.keys
5.end
6.end
Ruby代码1.arr = %w{foo bar baz bar baz qux foo zub}
2.puts arr.dups.inspect
3.# => ["baz", "foo", "bar"]Ruby代码1.#替换一
2.inject(Hash.new(0)) {|h,v| h += 1; h}.reject{|k,v| v==1}.keys这个是比较好理解的
Ruby代码1.class Array
2.def only_duplicates
3. duplicates = []
4. self.each {|each| duplicates << each if self.count(each) > 1}
5. duplicates.uniq
6.end
7.end
Ruby代码1.puts .only_duplicates.inspect
2.==>
Ruby代码1.require 'benchmark'
2.
3.module Enumerable
4. def map_with_index
5. index = -1
6. (block_given? && self.class == Range || self.class == Array)?map { |x| index += 1; yield(x, index) }:self
7. end
8.end
9.
10.
11.class Array
12.
13. def find_dups
14. inject(Hash.new(0)) { |h,e| h += 1; h }.select { |k,v| v > 1 }.collect { |x| x.first }
15. end
16.
17.
18.
19.
20. def find_dups2
21. uniq.select{ |e| (self-).size < self.size - 1 }
22. end
23.
24. def find_ndups # also returns the number of items
25. uniq.map { |v| diff = (self.size - (self-).size); (diff > 1) ? : nil}.compact
26. end
27.
28.
29. # cf. http://www.ruby-forum.com/topic/122008
30. def dups_indices
31. (0...self.size).to_a - self.uniq.map{ |x| index(x) }
32. end
33.
34. def dup_indices(obj)
35. i = -1
36. ret = map { |x| i += 1; x == obj ? i : nil }.compact
37. #ret = map_with_index { |x,i| x == obj ? i : nil }.compact
38. ret.shift
39. ret
40. end
41.
42. def delete_dups(obj)
43. indices = dup_indices(obj)
44. return self if indices.empty?
45. indices.reverse.each { |i| self.delete_at(i) }
46. self
47. end
48.
49.end
50.
51.
52.array =
53.
54.dups = nil
55.
56.
57.Benchmark.bm(14) do |t|
58.
59. t.report('find_dups:') do
60. dups = array.find_dups
61. end
62.
63.end
64.
65.p dups #=>
66.
67.
68.p %w(a b a c c d).dups_indices
69.p %w(a b a c c d).dup_indices('c')
70.p %w(a b a c c d).delete_dups('a')Ruby代码1.class Array
2.
3.def find_dups
4. uniq.map {|v| (self - ).size < (self.size - 1) ? v : nil}.compact
5.end
6.
7.endRuby代码1.def mostused(ahash)
2. original_size = ahash.size
3. sizes = {}
4. ahash.uniq.map { |x| sizes = original_size - ((ahash - ).size)}
5. sizes.sort_by {|k,v| v}.pop
6. end 牛呀！！太有才了.
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