Ruby if-statement, possible to shorten it further?

Question

Is it possible to shorten this, or to improve the code in any way? I know it's just a simple if-statement, but it's always fun to learn a shorter way of doing things.

if self.citizenship == 'ES'
  @identification_type = IDENTIFICATION_TYPES[0]
elsif self.country == 'ES'
  @identification_type = IDENTIFICATION_TYPES[1]
end

Answer 1

You could remove a little duplication like this:

@identification_type = if self.citizenship == 'ES'
  IDENTIFICATION_TYPES[0]
elsif self.country == 'ES'
  IDENTIFICATION_TYPES[1]
end

Answer 2

I don't know Ruby, so I'm not sure this is at all idiomatic. However, you can do something like this (if you're looking for a one-liner):

@identification_type = IDENT_TYPES[[@citizenship, @country].index('ES')]

Just so this makes some sort of sense (in case I didn't understand your code), here is some context:

IDENT_TYPES = {0 => :citizen, 1 => :country}

class Foo
    attr_accessor = :citizenship, :country, :identification_type

    def initialize(citizenship, country)
        @citizenship = citizenship
        @country = country
        @identification_type = IDENT_TYPES[[@citizenship, @country].index('ES')]
        puts @identification_type
    end
end

foo = Foo.new('ES', 'EN')
foo = Foo.new('EN', 'ES')
foo = Foo.new('EN', 'EN')

This outputs:

citizen
country
nil

Answer 3

You could replace the if with case. Normally, the case-statement contains a variable and the when-statements contain constant or variables. But you may do it the other was:

#Some code to make it executable
IDENTIFICATION_TYPES = [1,2]
class MyObject
  def citizenship; 'ES';end
  def country;  'ES';end
  attr_reader :identification_type

  def test
  #The code:
  @identification_type  = case 'ES'
    when self.citizenship
      IDENTIFICATION_TYPES[0]
    when self.country
      IDENTIFICATION_TYPES[1]
    end
  end
end

p MyObject.new.test

Advantage: you don't need to repeat the == 'ES'.

Disadvantage: Mixed checks (ES or AS...) is not possible.

Answer 4

Based on your code (somewhat like @AdamWagner's answer), here's a way without a case statement (though self.country is always evaluated):

criteria=[self.citizenship, self.country]
@identification_type=
 IDENTIFICATION_TYPES.at criteria.index{|e| 'ES'==e}

And a way with a case statement:

k=case 'ES'
  when self.citizenship then 0
  when self.country     then 1
  end
end
@identification_type=
 IDENTIFICATION_TYPES.at k