Group attributes


#1

Is it possible something like this:

group.set_attribute('katalog','zmienn',{:a1 =>1,:a2 =>2})

#2

NO, the symbol keys cannot be saved into an attribute dictionary.
But you can use string keys in a hash and save it as a JSON string in an attribute dictionary.
(You cannot have symbol keys in a JSON (JavaScript Object Notation) string because JSON uses ‘:’ instead of ‘=>’.)

require 'json'

h1 = {'a1' =>1,'a2' =>2}
j1 = h1.to_json
j1.inspect
#=> "{\"a1\":1,\"a2\":2}"
grp.set_attribute('katalog','zmienn',j1)

# Later ...
j2 = grp.get_attribute('katalog','zmienn')
h2 = JSON.parse(j2) # returns a Ruby hash object
h2.inspect
#=> {"a1"=>1, "a2"=>2}
h2.class
#=> Hash

So if you still want to use symbol keys in your hash, …

EDIT: (2018-01-12) @mamjankowski

I overlooked an option argument for JSON.parse() that WILL produce Ruby hashes using symbol keys.

ruby_hash = JSON.parse( json_str, symbolize_names => true )
# ... or for Ruby 2+ using named argument...
ruby_hash = JSON.parse( json_str, symbolize_names: true )

~

Custom methods to symbolize / stringify hash keys ... (click to expand) ...

(Collapsed on 2018-01-12 edit. No longer valid to discussion, but perhaps of geeky interest.)

… you will need (not really) to write your own methods to convert from JSON strings and hashes. OR just string keys to / from symbol keys, like:

def symbolize_keys(hash)
  h = {}
  hash.each {|k,v|
    h[k.to_sym]= v
  }
  h # return the new hash with symbol keys
end

def stringify_keys(hash)
  h = {}
  hash.each {|k,v|
    h[k.to_s]= v
  }
  h # return the new hash with string keys
end

Example html dialog (suite)
Loading components from a File
HtmlDialog.execute_script
Invalid Signature
#3

Thanks, Dan.


closed #4

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