create new object in rails

Question

I can't find a good example of this, so please point me in the right direction.

I want to create an object from scratch with 2 attributes abbr and name

I am trying to make an object with the 50 states and DC. Since I don't see this list changing every often, I don't see a need for a database, maybe I am wrong.

I have tried the following without success:

new_state = Object.new        
new_state.abbr = state[:abbr]     
new_state.name = state[:name]

and I get undefined method abbr=' for #<Object:0x00000006763008>

What am I doing wrong?

phil pirozhkov · Accepted Answer · 2011-11-08 06:13:20Z

5

Object in Ruby is quite different from the one in JavaScript which I assume you got used to, so it's not that simple to add properties on the fly. Hash, instead is very similar to an associative array in JS, and you can use it for your purposes:

states = Hash.new # or just {}
states[state[:abbr]] = state[:name] # {'MD' => 'Maryland'}
states['AL'] = 'Alaska' # {'MD' => 'Maryland', 'AL' => 'Alaska'}
states.keys # => ['MD', 'AL']
states.values # => ['Maryland', 'Alaska']
states['AL'] # => 'Alaska'

As you can see, Hash provides adding, finding and fetching out of the box, so you don't even have do define your own class. It's also a good idea to .freeze the contents once you've done adding the states to it.

answered Nov 8, 2011 at 6:13

phil pirozhkov

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mu is too short · Accepted Answer · 2019-03-17 17:48:20Z

5

You could create a simple class without a database behind it:

class State
  attr_accessor :abbr, :name
end

new_state = State.new
new_state.abbr = state[:abbr]
new_state.name = state[:name]

Your version doesn't work because Object doesn't have abbr= or name= methods and it won't make them up on the fly.

edited Mar 17, 2019 at 17:48

answered Nov 8, 2011 at 5:49

mu is too short

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1 Comment

Toby Joiner Over a year ago

As always, your comment was awesome. I just think the other way will be a better solution for me.

tolitius · Accepted Answer · 2011-11-08 05:49:44Z

2

you can use decoder that reads from/keeps its states/abbreviations/i18n in YAML.

Decoder.i18n = :en
country = Decoder::Countries[:US]
country.to_s
# => "United States"    

state = country[:MA]
state.to_s
# => "Massachusetts"

answered Nov 8, 2011 at 5:49

tolitius

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2 Comments

Toby Joiner Over a year ago

This is great, now is there one that does vehicle makes and models? haha

tolitius Over a year ago

there was an attempt to use KBB APIs

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