Variables, keywords and identifiers

Variables :

         * A variable allows us to store a value by assigning it to a name, which can be used later.

         * Programmers generally choose names for their variables that are meaningful.

         * Named memory locations to store values.

          * We don't need to declare a variable before using it. 

           

           * It can be of any length. No space is allowed.

Keywords :

          * Keywords are the reserved words in Python.

          * We cannot use a keyword as variable name, function name or any other

identifier.

          * They are used to define the syntax. 

  

Identifiers :

                    Identifier is the name given to entities  like class, functions, variables etc. in Python.

            

       * Identifiers can be a combination of letters in lowercase (a to z) or uppercase (A  to Z) or digits (0 to 9) or an underscore ( _ ). 

       * An identifier cannot start with a digit. 

     

       *Keywords can't be used as identifiers

 

        *Cannot use special symbols like !, @, #, $, % etc. in our identifier.

         *Identifier can be of any length.