Variable is a label which helps to store data. To create a variable, we can assign it a value with the help of assignment operator. Based on the type of value assigning, the memory will dynamically allocate for the variable

Example:

roll_number = 12345

# roll_number is a variable
# = is an assignment operator
# 12345 is the value stored in roll_number variable

Rules for Variable Creation

• Lowercase or uppercase or digits or underscore A Variable name can only contain lowercase (a to z) or uppercase (A to Z) or digits (0 to 9) or an underscore (_)
• No digit start A variable name cannot start with a digit (0 to 9)
• Lowercase and uppercase or underscore start 3. A variable name can start with a lowercase (a to z) or uppercase (A to Z) or an underscore (_)
• Case-Sensitive Variable name is case-sensitive (a = 5, A=6 -> a and A are two different variables in python)
• No Special Characters The variable name cannot have special characters such as !, @, #, $, % etc..

Multiple Assignment

We can assign values to multiple variables in a single line like this a = b = c = 100

#Multiple Assignment with single value
a=b=c=100
print(a, b, c)

#Multiple Assignment with multiple value
a, b, c = 10, 20, 30
print(a, b, c)

Output

100 100 100
10 20 30

Constants in Python

Constant is a value that remains the same which cannot change or modify once it get declared. Python don't have constant declaration as like in Java. We can declare a variable or value as constant in Python and make sure which don't get the modification.

Rules - Constant variables should have only capital letters and underscores (for word separation)

#Constant Example
PI = 3.14
print(PI)

Output

3.14