In programming languages, 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. (However, it is preferred to keep it short and meaningful).
• It should not be a keyword or reserved word given in Table.
• We cannot use special symbols like !, @, #, $, %, etc., in identifiers.
For example, to find the average of marks obtained by a student in three subjects, we can choose the identifiers as marks1, marks2, marks3 and avg rather than a, b, c, or A, B, C.
avg = (marks1 + marks2 + marks3)/3
Similarly, to calculate the area of a rectangle, we can use identifier names, such as area, length, breadth instead of single alphabets as identifiers for clarity and more readability.
area = length * breadth
