CODEWITHSUNDEEP
ruby-on-railsruby
Sergey M
Sergey M

Reputation: 521

How to initialize class variable through class method in Ruby

Is there a simple way to initialize a class variable through a class method in Ruby? I'm trying this:

class MyClass
    @@product_families = MyClass.load_pgrollups(File.join(File.dirname(__FILE__), ASSETS_FOLDER_NAME, PGROLLUP_CSV_FILENAME))

    def self.load_pgrollups(csv_file)                                                                                                                                        
       ....

       return product_families
    end

I'm getting an exception: undefined method `load_pgrollups' for ModuleName::myClass:Class

I don't necessarily want to initialize a class variable. I also tried to initialized a constant in a module through a module function

module ModuleName
    PRODUCT_FAMILIES = load_pgrollups(File.join(File.dirname(__FILE__), ASSETS_FOLDER_NAME, PGROLLUP_CSV_FILENAME))

    def load_pgrollups(csv_file)                                                                                                                                        
       ....

       return product_families
    end

but I got undefined method `load_pgrollups' for MyModule:Module

Upvotes: 2

Views: 770

Answers (2)

Jörg W Mittag
Jörg W Mittag

Reputation: 369458

You define the method in line 4, but you are already calling it in line 2, where it hasn't been defined yet. So, yes, the method is undefined at the point you are calling it.

Upvotes: 2

sawa
sawa

Reputation: 168101

Call it after it is defined:

class myClass
  def self.load_pgrollups(csv_file)                                                                                                                                        
    ....
    return product_families
  end
  @@product_families = load_pgrollups(File.join(__dir__, ASSETS_FOLDER_NAME, PGROLLUP_CSV_FILENAME))
end

Upvotes: 5

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