```Hi --

On Mon, 18 Jun 2007, Harry Kakueki wrote:

> On 6/18/07, Gilbert Lau <gilbertlsk / gmail.com> wrote:
>> Thanks a lot. Sorry, got another question
>>
>> let's say that the hash is
>>
>> myhash = {"a" => [[0,0],[3,4]], "b" => [[1,1],[9,8]], "c" => [[7,6]]}
>>
>> how do I sort the values to become
>>
>> [0,0],[1,1],[3,4],[7,6],[9,8]
>>
>> and be able to recall the keys to arrange according to the sorted
>> values, like
>>
>> "a", "b", "a", "c", "b"
>>
>
> Well, I think this will work.
> Extract the arrays from the values and then sort.
>
> myhash = {"a" => [[0,0],[3,4]], "b" => [[1,1],[9,8]], "c" => [[7,6]]}
>
> arr = []
> myhash.each_value do |x|
> x.each {|y| arr << y}
> end
>
> p arr.sort!
>
> # This will find whether it is included in "a" for example
> # but you need to think about what to do if you have duplicates.
> # myhash = {"a" => [[0,0],[3,4]], "b" => [[1,1],[0,0],[9,8]], "c" => [[7,6]]}
>
>
> # This is ugly but maybe you can get some ideas
> arr.each do |c|
> p "FROM a" if myhash["a"].include?(c)
> p "NOT FROM a" unless myhash["a"].include?(c)
> end

One way to generalize it:

arr.sort.map {|c| myhash.keys.find {|k| myhash[k].include?(c) } }

There's probably a more efficient way (there usually is when I'm the
first to suggest these things :-) but that will get you the whole
array.

David

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