Assigning session hash to a variable doesn't keep modified hash in session

ruby-talk
1

Hey all,

I basically have some nested hashes stored in the session variable:

def set_code(unit_id, code)

     if session[:code].select {|h| h[unit_id]}.empty?
       session[:code] << { unit_id => {}}
     end

      case code
      when 3,4
        session[:code].detect {|h| h[unit_id]}[unit_id][:code_a] ||= []
        session[:code].detect {|h| h[unit_id]}[unit_id][:code_a] << code
      when 8,9
        session[:code].detect {|h| h[unit_id]}[unit_id][:code_b] ||= []
        session[:code].detect {|h| h[unit_id]}[unit_id][:code_b] << code
      end
  end

From the code above, you can see four lines of repetitive code. The
problem is if I did this:

unit_hash = session[:code].detect {|h| h[unit_id]}[unit_id]

case code
when 3,4
  unit_hash[:code_a] ||= []
  unit_hash[:code_a] << code
when 8,9
  unit_hash[:code_b] ||= []
  unit_hash[:code_b] << code
end

Then the appended code will not be stored in the session.

Any way to refactor this so I dont have 4 repetitive lines of code?

Thanks for response

···

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2

Put the result of repetitive code in a variable. This might do the same:

def set_code(unit_id, code)
  s_code = session[:code]
  unit_id_hash = s_code.detect {|h| h[unit_id]}

  if unit_id_hash.nil?
    unit_id_hash = {}
    s_code << {unid_id => unit_id_hash}
  end

  # this lookup could be done via a constant Hash as well
  key = case code
    when 3,4
      :code_a
    when 8,9
      :code_b
    end

  unit_id_hash[key] << code if key
end

But frankly, your data structure looks suspicious to me. For example:
why is session[:code] an Array containing of Hashes with only one key
value pair? Why don't you make it a Hash where indexed by code?

Kind regards

robert

···

On Sun, Oct 9, 2011 at 11:28 PM, John Merlino <stoicism1@aol.com> wrote:

Hey all,

I basically have some nested hashes stored in the session variable:

def set_code(unit_id, code)

if session\[:code\]\.select \{|h| h\[unit\_id\]\}\.empty?
  session\[:code\] &lt;&lt; \{ unit\_id =&gt; \{\}\}
end

 case code
 when 3,4
   session\[:code\]\.detect \{|h| h\[unit\_id\]\}\[unit\_id\]\[:code\_a\] ||= \[\]
   session\[:code\]\.detect \{|h| h\[unit\_id\]\}\[unit\_id\]\[:code\_a\] &lt;&lt; code
 when 8,9
   session\[:code\]\.detect \{|h| h\[unit\_id\]\}\[unit\_id\]\[:code\_b\] ||= \[\]
   session\[:code\]\.detect \{|h| h\[unit\_id\]\}\[unit\_id\]\[:code\_b\] &lt;&lt; code
 end

end

From the code above, you can see four lines of repetitive code. The
problem is if I did this:

unit_hash = session[:code].detect {|h| h[unit_id]}[unit_id]

case code
when 3,4
unit_hash[:code_a] ||=
unit_hash[:code_a] << code
when 8,9
unit_hash[:code_b] ||=
unit_hash[:code_b] << code
end

Then the appended code will not be stored in the session.

Any way to refactor this so I dont have 4 repetitive lines of code?

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/