Ruby Variables

Ruby has a number of different types of variables that are available to us. Five to be specific. I find a list helpful to assist me in remembering when to use which one and when I shouldn’t, so I hope it’s helpful to you also.

Local Variables

-A local variable has a name starting with a lower case letter or an underscore character (_). Local variables do not, like globals and instance variables, have the value nil before initialization

Instance Variables

-Instance variables begin with @. Uninitialized instance variables have the value nil

Class Variable

-Class variables begin with @@ and must be initialized before they can be used in method definitions.

- Class variables are shared among descendants of the class or module in which the class variables are defined. -Referencing an uninitialized class variable produces an error.

Global Variables

-Global variables begin with $. Uninitialized global variables have the value nil

-Assignment to global variables alters global status. It is not recommended to use global variables.

Constants

-Constants defined within a class or module can be accessed from within that class or module, and those defined outside a class or module can be accessed globally

-Constants may not be defined within methods. Referencing an uninitialized constant produces an error. Making an assignment to a constant that is already initialized produces a warning.

We’ve now gone over each type of ruby variable available to us, I hope this helps you know the difference between each! Thanks for reading, happy coding!