问题
I have a Ruby array which contains duplicate elements.
array = [1,2,2,1,4,4,5,6,7,8,5,6]
How can I remove all the duplicate elements from this array while retaining all unique elements without using for-loops and iteration?
回答1:
array = array.uniq
The uniq method removes all duplicate elements and retains all unique elements in the array.
One of many beauties of Ruby language.
回答2:
You can also return the intersection.
a = [1,1,2,3]
a & a
This will also delete duplicates.
回答3:
You can remove the duplicate elements with the uniq method:
array.uniq # => [1, 2, 4, 5, 6, 7, 8]
What might also be useful to know is that the uniq method takes a block, so e.g if you a have an array of keys like this:
["bucket1:file1", "bucket2:file1", "bucket3:file2", "bucket4:file2"]
and you want to know what are the unique files, you can find it out with:
a.uniq { |f| f[/\d+$/] }.map { |p| p.split(':').last }
回答4:
If someone was looking for a way to remove all instances of repeated values, see this question.
a = [1, 2, 2, 3]
counts = Hash.new(0)
a.each { |v| counts[v] += 1 }
p counts.select { |v, count| count == 1 }.keys # [1, 3]
回答5:
Just another alternative if anyone cares.
You can also use the to_set method of an array which converts the Array into a Set and by definition, set elements are unique.
[1,2,3,4,5,5,5,6].to_set => [1,2,3,4,5,6]
回答6:
Try with XOR Operator in Ruby:
a = [3,2,3,2,3,5,6,7].sort!
result = a.reject.with_index do |ele,index|
res = (a[index+1] ^ ele)
res == 0
end
print result
来源：https://stackoverflow.com/questions/8365721/remove-duplicate-elements-from-array-in-ruby