Ruby: Passing same parameters to multiple methods inside a class

Question

Sorry if this is too basic to ask. Say, I have 5 methods inside a same class. When I call each method, I need to pass the same parameters. Is there a way to simplify this and avoid the repetition?

class Class1
        def method1(arg1, arg2, arg3)
                puts arg1, arg2, arg3
        end
        def method2(arg1, arg2, arg3)
                puts arg1, arg2, arg3
        end
        def method3(arg1, arg2, arg3)
                puts arg1, arg2, arg3
        end
        def method4(arg1, arg2, arg3)
                puts arg1, arg2, arg3
        end
        def method5(arg1, arg2, arg3)
                puts arg1, arg2, arg3
        end
end

obj1 = Class1.new

obj1.method1(1, 2, 3)
obj1.method2(4, 5, 6)
obj1.method3(7, 8, 9)
obj1.method4(10, 11, 12)
obj1.method5(13, 14, 15)

Thanks in advance!

What do you mean by the same parameters? In the example you pass different ones to each method - to method 1,2,3, to method2 4,5,6 etc — mrzasa
– mrzasa, Commented Oct 11, 2019 at 18:37
mrzasa, I meant to pass the same parameters to each method inside the same class. — Steve
– Steve, Commented Oct 11, 2019 at 19:48
You can format your code however you like but the Ruby convention is to indent two spaces. — Cary Swoveland
– Cary Swoveland, Commented Oct 11, 2019 at 21:35

ArtuX · Accepted Answer · 2019-10-11 20:11:38Z

2

Using constructor might be helpful:

class MyClass

  def initialize(arg1, arg2, arg3)
    @arg1, @arg2, @arg3 = arg1, arg2, arg3
  end

  def method_one
    puts @arg1, @arg2, @arg3
  end

  def method_two
    puts @arg1, @arg2, @arg3
  end

end

my_obj = MyClass.new(1,7,13)
my_obj.method_one  #=> 1 7 13 
my_obj.method_two  #=> 1 7 13

You can also be more succinct using Struct:

MyClass = Struct.new(:arg1, :arg2, :arg3) do

  def method_one
    puts arg1, arg2, arg3
  end

  def method_two
    puts arg1, arg2, arg3
  end

end

my_obj = MyClass.new(1,7,13)
my_obj.method_one  #=> 1 7 13 
my_obj.method_two  #=> 1 7 13
puts my_obj.arg2   #=> 7

edited Oct 11, 2019 at 20:11

answered Oct 11, 2019 at 18:41

ArtuX

3742 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Myst · Accepted Answer · 2019-10-11 20:02:46Z

EDIT: I just notices pjs's answer (I skimmed the beginning and somehow missed the content)... go up-vote that one, it was here first and it's the same solution.

If you don't control the class (you can't use class instance variables), consider using the splat (*) operator.

i.e.:

class MyClass
    def mthd1(arg1,arg2,arg3)
      #...
    end
    def mthd2(arg1,arg2,arg3)
      #...
    end
    def mthd3(arg1,arg2,arg3)
      #...
    end
    def mthd4(arg1,arg2,arg3)
      #...
    end
end
foo = MyClass.new
args_to_pass = [1,2,3]
foo.mthd1(*args_to_pass)
foo.mthd2(*args_to_pass)
foo.mthd3(*args_to_pass)
foo.mthd4(*args_to_pass)

Or even monkey patch the class to add a method that does it for you (untested):

class MyClass
   # monkey patching
   MULTI_METHOD_NAMES = [:mthd1, :mthd2, :mthd3, :mthd4]
   def multi_func *args
       MULTI_METHOD_NAMES {|m| self.send(m, *args)
   end    
end
# use:
foo = MyClass.new
foo.multi_func(1, 2, 3)

pjs · Accepted Answer · 2019-10-11 19:06:38Z

1

Your example doesn't agree with your statement that you want the same arguments, but I'm charging ahead with an alternate implementation of your example.

class Klass
  # slightly more descriptive output from the methods...
  def method1(a1, a2, a3)
    puts "in method1"
    puts "#{a1}, #{a2}, #{a3}"
  end

  def method2(a1, a2, a3)
    puts "in method2"
    puts "#{a1}, #{a2}, #{a3}"
  end

  def method3(a1, a2, a3)
    puts "in method3"
    puts "#{a1}, #{a2}, #{a3}"
  end
end

# store the method symbols and arguments in arrays...   
m = [:method1, :method2, :method3]
args = [1, 2, 3]

obj = Klass.new
# ...which allows us to iterate over them.
m.each do |method|
  obj.send(method, *args)
  args.map! { |x| x + 3 }  # update the args as in the given example
end

produces:

in method1
1, 2, 3
in method2
4, 5, 6
in method3
7, 8, 9

answered Oct 11, 2019 at 19:06

pjs

20k4 gold badges30 silver badges64 bronze badges

1 Comment

Steve Over a year ago

pjs, thank you as well for the good example but my intention was to simplify the code and avoid the repetition of passing the same parameters to each method over and over, as shown in my example and also in your example.

Collectives™ on Stack Overflow

Ruby: Passing same parameters to multiple methods inside a class

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related