Python Identifiers

It is a name given to entities like class, variables, module or other object. The identifier is a combination of character digits and underscore. The identifier should start with a character or Underscore then use digit. It starts with a letter A to Z or a to z or an underscore (_) followed by zero or more letters, underscores and digits (0 to 9).

Python does not allow punctuation characters such as @, $, and % within identifiers. Python is a case sensitive programming language. 

Rules for naming conventions for Python identifiers:-

  • Except class name all other identifiers starts with a lowercase letter.
  • An identifier cannot start with a digit. 1variable is invalid, but variable1 is a valid name.
  • Starting an identifier with a single leading underscore indicates that the identifier is private.
  • Starting an identifier with two leading underscores indicates a strongly private identifier.
  • An identifier can be of any length.
  • Keywords cannot be used as identifiers.
global = 12

Output:

File "<interactive input>", line 1

        global=1
          ^
SyntaxError: invalid syntax
  • We cannot use special symbols like !, @, #, $, % etc. in our identifier.
a@=0

Output:

 File "<interactive input>", line 1
    a@ = 0
     ^
SyntaxError: invalid syntax

Example of correct identifiers

var1
_var1
_1_var
var_1

Example of incorrect identifiers

!var1
1var
1_var
var#1
Tags
Python