how to print elements of a class variable array in ruby

Question

I have just started learning ruby and I am unable to find out a solution on printing first_name and last_name for each element of @@people array...

class Person
    #have a first_name and last_name attribute with public accessors
    attr_accessor :first_name, :last_name

    #have a class attribute called `people` that holds an array of objects
    @@people = []

    #have an `initialize` method to initialize each instance
    def initialize(x,y)#should take 2 parameters for first_name and last_name
    #assign those parameters to instance variables
      @first_name = x
      @last_name = y
      #add the created instance (self) to people class variable
      @@people.push(self)
    end

    def print_name
      #return a formatted string as `first_name(space)last_name`
      # through this method i want to print first_name and last_name
    end  
end

p1 = Person.new("John", "Smith")
p2 = Person.new("John", "Doe")
p3 = Person.new("Jane", "Smith")
p4 = Person.new("Cool", "Dude")



# Should print out
# => John Smith
# => John Doe
# => Jane Smith
# => Cool Dude

The assignment as stated is impossible. Returning a string from print_name cannot possibly print out anything to the console. The assignment cannot be completed as stated. — Jörg W Mittag
– Jörg W Mittag, Commented Apr 1, 2020 at 18:30

Sebastián Palma · Accepted Answer · 2020-04-01 08:58:25Z

2

Why would you make the class Person to hold an array of persons?

It's easier if you just wrap your person objects in an array and then iterate over them and invoke their first_name and last_name accessors:

class Person
  attr_accessor :first_name, :last_name

  def initialize(first_name, last_name)
    @first_name = first_name
    @last_name = last_name
  end
end

p1 = Person.new("John", "Smith")
p2 = Person.new("John", "Doe")
p3 = Person.new("Jane", "Smith")
p4 = Person.new("Cool", "Dude")

[p1, p2, p3, p4].each { |person| p "#{person.first_name} #{person.last_name}" }
# "John Smith"
# "John Doe"
# "Jane Smith"
# "Cool Dude"

answered Apr 1, 2020 at 8:58

Sebastián Palma

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3 Comments

ravi Over a year ago

I' m new to ruby and it's my homework to do in the prescribed way...I even searched google but I' m unable to get through...

Sebastián Palma Over a year ago

Give me a hand then. Should you instantiate them separately? Or you can directly pass the number of persons to be isntantiated and then push them to @@people?

Sebastián Palma Over a year ago

The problem is @@people is directly attached to a single instance of person. Anyway, you can try moving the class variable outside the class, not impossible, but also not recommended at all.

@@people = []  class Person   attr_accessor :first_name, :last_name    def initialize(x, y)     @first_name = x     @last_name = y     @@people.push(self)   end    def print_name     p "#{first_name} #{last_name}"   end   end  p1 = Person.new("John", "Smith") p2 = Person.new("John", "Doe") p3 = Person.new("Jane", "Smith") p4 = Person.new("Cool", "Dude")  @@people.each(&:print_name)

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