From: RK Sentinel <sentinel.2001@...>
Date: 2009-01-24T19:03:24+09:00
Subject: Sorting array with nils

I have been browsing but given answers are not suiting me.

I hava a double dim array like a dataset.
I thus *cannot* use compact since that would knock off rows. Some
answers say a nil cannot be compared to another datatype so the question
of putting such rows at the beginning or end does not arise.

I am trying to check for nils and using a "false/true" or -1/1 etc but
all are giving errors. Could someone help me out with this.

  def sort categ, column, descending=false
    d = get_records_for_category categ
    d = d.sort { |y,x|
      if descending
        if x[column].nil?
          true   # <<<<------------- errors
        elsif y[column].nil?
          false
        else
          x[column] <=> y[column]
        end
      else
        if x[column].nil?
          1     # <<<-------------- gives errors
        elsif y[column].nil?
          -1
        else
          y[column] <=> x[column]
        end
      end
    }
    return d
  end

Since its a double dim array, i cannot say what the datatype will be:
can be string, fixnum, date or true/false.

I figured since "A" <=> "B" reutrns -1,0 or 1, i should also put one of
these in the loop but it throws an error.

thanks.
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