This question already has an answer here:
这个问题已经有了答案:
- Ruby: How to find and return a duplicate value in array? 17 answers
- Ruby:如何在数组中找到并返回一个重复的值?17个答案
I've got an array A. I'd like to check if it contains duplicate values. How would I do so?
我有一个数组a,我想检查它是否包含重复的值。我该怎么做呢?
4 个解决方案
#1
115
Just call uniq
on it (which returns a new array without duplicates) and see whether the uniq
ed array has less elements than the original:
只需调用uniq(它返回一个没有重复的新数组)并查看uniqed数组的元素是否比原始数组少:
if a.uniq.length == a.length
puts "a does not contain duplicates"
else
puts "a does contain duplicates"
end
Note that the objects in the array need to respond to hash
and eql?
in a meaningful for uniq
to work properly.
注意数组中的对象需要响应散列和eql?这对uniq来说是有意义的工作。
#2
33
In order to find the duplicated elements, I use this approach (with Ruby 1.9.3):
为了找到重复的元素,我使用了这种方法(使用Ruby 1.9.3):
array = [1, 2, 1, 3, 5, 4, 5, 5]
=> [1, 2, 1, 3, 5, 4, 5, 5]
dup = array.select{|element| array.count(element) > 1 }
=> [1, 1, 5, 5, 5]
dup.uniq
=> [1, 5]
#3
9
If you want to return the duplicates, you can do this:
如果你想要返回副本,你可以这样做:
dups = [1,1,1,2,2,3].group_by{|e| e}.keep_if{|_, e| e.length > 1}
# => {1=>[1, 1, 1], 2=>[2, 2]}
If you want just the values:
如果你只想要值:
dups.keys
# => [1, 2]
If you want the number of duplicates:
如果你想要复制的数量:
dups.map{|k, v| {k => v.length}}
# => [{1=>3}, {2=>2}]
#4
4
Might want to monkeypatch Array if using this more than once:
如果多次使用monkeypatch数组:
class Array
def uniq?
self.length == self.uniq.length
end
end
Then:
然后:
irb(main):018:0> [1,2].uniq?
=> true
irb(main):019:0> [2,2].uniq?
=> false
#1
115
Just call uniq
on it (which returns a new array without duplicates) and see whether the uniq
ed array has less elements than the original:
只需调用uniq(它返回一个没有重复的新数组)并查看uniqed数组的元素是否比原始数组少:
if a.uniq.length == a.length
puts "a does not contain duplicates"
else
puts "a does contain duplicates"
end
Note that the objects in the array need to respond to hash
and eql?
in a meaningful for uniq
to work properly.
注意数组中的对象需要响应散列和eql?这对uniq来说是有意义的工作。
#2
33
In order to find the duplicated elements, I use this approach (with Ruby 1.9.3):
为了找到重复的元素,我使用了这种方法(使用Ruby 1.9.3):
array = [1, 2, 1, 3, 5, 4, 5, 5]
=> [1, 2, 1, 3, 5, 4, 5, 5]
dup = array.select{|element| array.count(element) > 1 }
=> [1, 1, 5, 5, 5]
dup.uniq
=> [1, 5]
#3
9
If you want to return the duplicates, you can do this:
如果你想要返回副本,你可以这样做:
dups = [1,1,1,2,2,3].group_by{|e| e}.keep_if{|_, e| e.length > 1}
# => {1=>[1, 1, 1], 2=>[2, 2]}
If you want just the values:
如果你只想要值:
dups.keys
# => [1, 2]
If you want the number of duplicates:
如果你想要复制的数量:
dups.map{|k, v| {k => v.length}}
# => [{1=>3}, {2=>2}]
#4
4
Might want to monkeypatch Array if using this more than once:
如果多次使用monkeypatch数组:
class Array
def uniq?
self.length == self.uniq.length
end
end
Then:
然后:
irb(main):018:0> [1,2].uniq?
=> true
irb(main):019:0> [2,2].uniq?
=> false