How to use global variables in Ruby?

Global variables have a global scope and they can be accessed from anywhere in a program. Assignments to global variables can be made from anywhere in the program. Global variables are always prefixed with a dollar sign.

It is necessary to define a global variable to have a variable that is available across classes. When a global variable is uninitialized, it has no value by default and its use is nil.

Now let's make use of the global variable in an example to understand it better. Consider the code shown below.

Example 1

# Global Variable example # global variable $global_var = 15 # Defining first class class FirstClass    def print_global_variable       puts "Global variable in FirstClass is #$global_var"    end end # Defining second Class class SecondClass    def print_global_variable       puts "Global variable in SecondClass is #$global_var"    end end # Creating object firstclassobj = FirstClass.new firstclassobj.print_global_variable # Creating another object secondclassobj = SecondClass.new secondclassobj.print_global_variable

Output

Global variable in FirstClass is 15 Global variable in SecondClass is 15

Example 2

Now, let's explore one more example of a global variable in Ruby. Consider the code shown below.

# global variable example $global_var = "Tutorial" # Defining Class class Teacher    def instance_method       puts "Available? #{$global_var}, #{$some_global_var}"    end    def self.class_method       $some_global_var = "Welcome to TutorialsPoint"       puts "Available? #{$global_var}"    end end Teacher.class_method

Output

Available? Tutorial