Discovering Ruby object members?

Question

What is an easy way to find out what methods/properties that a ruby object exposes?

As an example to get member information for a string, in PowerShell, you can do

"" | get-member

In Python,

dir("")

Is there such an easy way to discover member information of a Ruby object?

Answer 1

"foo".methods

See:

http://ruby-doc.org/core/classes/Object.html

http://ruby-doc.org/core/classes/Class.html

http://ruby-doc.org/core/classes/Module.html

Answer 2

Ruby doesn't have properties. Every time you want to access an instance variable within another object, you have to use a method to access it.

Answer 3

Two ways to get an object's methods:

my_object.methods
MyObjectClass.instance_methods

One thing I do to prune the list of inherited methods from the Object base class:

my_object.methods - Object.instance_methods

To list an object's attributes:

object.attributes

Answer 4

There are two ways to accomplish this:

obj.class.instance_methods(false), where 'false' means that it won't include methods of the superclass, so for example having:

class Person
  attr_accessor :name
  def initialize(name)
    @name = name
  end
end

p1 = Person.new 'simon'
p1.class.instance_methods false # => [:name, :name=]
p1.send :name # => "simon"

the other one is with:

p1.instance_variables # => [:@name]
p1.instance_variable_get :@name # => "simon"

Answer 5

Use this:

my_object.instance_variables

Answer 6

object.methods

will return an array of methods in object