David Walden

Ruby Classes

March 20, 2016

Instance Variables vs. Local Variables

A Ruby class is a framework for creating new objects. Instance variables are accessible within a particular instance of a class and are created within the instance. All methods defined within a class have access to the instance variables of that class. Instance variables represent the attributes of real-world objects, while methods describe the behaviors. Ruby classes are used to bind new methods to objects or types of objects.

An instance variable can be used anywhere within the instance of a class in which they are defined. Instance variables have an “@” at the beginning of the variable name. If you need to access a variable in multiple methods within a class, use an instance variable. If you only need to access the variable within a single method, use a local variable.

Here’s an example of how you would use a local variable:

              class Example1
                def initialize
                  local_variable = "hello"
                  puts local_variable
                end
              end
            

Here’s an example of how you would use an instance variable:

              class Example2
                def initialize
                  @instance_variable = "hello"
                end

                def greeting
                  puts @instance_variable
                end
              end