Trying to solve this problem,
class Person def initialize(name) @name=name end def greet(other_name) puts "Hi #{other_name}, my name is #{name}" end end initialize("ak") greet("aks") but I am getting the error like:
ArgumentError: wrong number of arguments calling `initialize` (1 for 0) I don't understand what is asking here, if its just the argument then why the error is like (1 for 0). can someone help me understand this problem.
Look at this code:
class Person attr_reader :name def initialize( name ) puts "Initializing Person instance #{object_id}" @name = name end def greet( name ) puts "Hi #{name}, I'm #{name()}" end end When you wrote initialize without explicit receiver:
initialize( "ak" ) It was only a matter of luck that your message was recognized. Look who has responded:
method( :initialize ).owner #=> BasicObject BasicObject, the foremother of all Object instances, herself responded to your call, by scolding you about wrong number of arguments, because:
method( :initialize ).arity #=> 0 Not only this method does not expect any arguments, but also you are not expected to call it at all. In fact, you are not expected to call #initialize on any object by yourself, save for exceptional situations. Class#new method handles calling of Person#initialize method for you:
A = Person.new( 'Abhinay' ) Initializing Person instance -605867998 #=> #<Person:0xb7c66044 @name="Abhinay"> Person.new handled creation of a new instance and automatically called its #initialize method. Also, #initialize method is created private, even if you did not specify it explitcitly. The technical term for such irregular behavior is magic. Person#initialize is magically private:
A.initialize( 'Fred' ) NoMethodError: private method `initialize' called for #<Person:0xb7c66044 @name="Abhinay"> You cannot just reinitialize yourself to 'Fred', you know. All other methods are public unless prescribed otherwise:
A.greet "Arup" Hi Arup, I'm Abhinay #=> nil You need to call the methods on the object (not just call the methods) and initialize is automatically called when creating a new object:
p = Person.new("ak") p.greet("aks") #=> "Hi aks, my name is ak" The problem is that to create new object you need to call method new on class, and not initialize on the object.
So code looks like this:
p = Person.new("John") Please, take a look at code below:
class Person attr_reader :name def initialize(name) @name = name end def greet(other_name) puts "Hi #{other_name}, my name is #{name}" end end person = Person.new("ak") person.greet("aks") #=> Hi aks, my name is ak