From: Robert Klemme <shortcutter@...>
Date: 2011-03-23T21:11:02+09:00
Subject: Re: Counting values in an array, storing in a hash then making an array of hashes?

On Mon, Mar 21, 2011 at 9:33 PM, Jen <jen.bottom@gmail.com> wrote:
> Hello,
>
> Apologies but i've run in to another problem while attempting to make a
> sudoku solver that uses basic genetic programming.
>
> This time I'm trying to count how many times each number occures in each
> board (boards stored in @offspring) then store the results in a hash.
>
> I think each hash is being overwritten because the keys are the same, so I'm
> attempting to store an array of hashes.
>
> I think I'm close, but my logic is still a bit off, as the length of my
> array of hashes is 1 but I expect it to be 4, with each element containing a
> hash. 4 is the size of the test population I am using, so there are 4 boards
> in @offspring.
>
> I could have probably done the same thing with an array, but I confused
> myself thinking about it :(
>
> My code so far:
>
> def fitness_check
> hashes = Array.new
> count = Hash.new 0
> #Adds another loop to ensure all elements of offspring are checked
> separetly.
> i = 0
> #loop through every row of offspring (first to fourth element)
> @offspring[i.to_i].each do |r|
> #loop through every column of every row
> r.each do |c|
> #Count the numbers in each column
> count[c] += 1
> hashes[i] = count
> end
> end
>
> #Need to stop the values in count getting overwritten by the next element in
> @offspring
> puts hashes.inspect
> puts hashes.length
> end
>
> Thanks in advance for any suggestions.

I'm not 100% positive that this is what you want, but it looks
suspiciously like what 7stud posted so here we go:

def fitness_check
  # loop to ensure all elements of offspring are checked separetly.
  hashes = @offspring.map do |board|
    Hash.new(0).tap do |count|

      # loop through every row of offspring (first to fourth element)
      board.each do |r|
        # loop through every column of every row
        r.each do |c|
          # Count the numbers in each column
          count[c] += 1
        end
      end

      count
    end
  end

  # debug output
  puts hashes.length
  p hashes
end

Kind regards

robert

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