Identifiers

Identifiers are names used to identify a variable, function, or other entities in a program.

The rules for naming an identifier in Python are as follows: 

• The name should begin with an uppercase or a lowercase alphabet or an underscore sign (_). This may be followed by any combination of characters a–z, A–Z, 0–9 or underscore (_). Thus, an identifier cannot start with a digit. 
• It can be of any length . 
• It should not be a keyword or reserved word . 
• We cannot use special symbols like !, @, #, $, %, etc., in identifiers.

Examples of identifiers:

• area
• _breadth
• mark_1