什么是Ruby（1.8.7）与C＃/。NET中的SortedDictionary类似？

Question

I need to hold values in sorted hash in ruby (1.8.7). What data structed will fit the best?

Answer 1

There is nothing in the core library or the standard library now, that will fit your bill.

There is , however, a feature request to add a Red/Black-Tree implementation to Ruby 1.9.3/2.0.

If you are able to force your users to only ever use XRuby or JRuby , you could just use one of the implementations of Java's java.util.SortedMap<K, V> such as java.util.TreeMap<K, V> .

If you are able to force your users to only ever use Ruby.NET or IronRuby , you could just use .NET's System.Collections.Generic.SortedDictionary<TKey, TValue> .

If you are able to force your users to only ever use MRI or YARV, you could use the Ruby/RBTree library. It might also work on Rubinius or the not-yet-released JRuby 1.6 . Note that there seem to be multiple independent updated forks of that library in the wild. It is not obvious, which one of those is the most recent and/or best maintained one.

The only solution I know of which is guaranteed to be portable, is Kanwei Li's Algorithms and Containers GSoC 2008 project , which actually contains two implementations of a sorted, key-indexed collection: Containers::RBTreeMap based on a Red/Black-Tree and Containers::SplayTreeMap based on a Splay Tree .

Answer 2

You might have to roll this yourself, if no one else has a better suggestion.

class SortedHash
  def initialize
    @data = []
  end

  def [](k)
    @data.find {|kp,vp| kp == k}.last
  end

  def []=(k, v)
    @data.reject! {|kp,vp| kp == k}
    @data << [k, v]
    @data = @data.sort_by {|kp,vp| kp}
  end

  def each(&b)
    @data.each(&b)
  end
end

sh = SortedHash.new
sh[32] = "no"
sh[1] = "later"
sh[99] = "after"

sh.each do |k,v|
  p [k,v]
end

Output:

[1, "later"]
[32, "no"]
[99, "after"]

Array is sorted by keys, so they can be of any call and you just need to define comparison operators on them.

Answer 3

Use the same class in c# SortedDictionary :

SortedDictionary keyValues = new SortedDictionary();

        keyValues.Add(5,"sample5");
        keyValues.Add(2, "sample2");
        keyValues.Add(6, "sample6");
        keyValues.Add(8, "sample8");
        keyValues.Add(9, "sample9");
        keyValues.Add(1, "sample1");