Python Variables

In Python, variables are used to store data that can be referenced and manipulated during program execution. A variable is essentially a name that is assigned to a value.

• Unlike Java and many other languages, Python variables do not require explicit declaration of type.
• The type of the variable is inferred based on the value assigned.

x = 5

name = "Samantha"  

print(x)

print(name)

5
Samantha

Rules for Naming Variables

To use variables effectively, we must follow Python’s naming rules:

1. Variable names can only contain letters, digits and underscores (_).
2. A variable name cannot start with a digit.
3. Variable names are case-sensitive like myVar and myvar are different.
4. Avoid using Python keywords like if, else, for as variable names.

Below listed variable names are valid:

age = 21
_colour = "lilac"
total_score = 90

Below listed variables names are invalid:

1name = "Error"  # Starts with a digit
class = 10       # 'class' is a reserved keyword
user-name = "Doe"  # Contains a hyphen

Assigning Values to Variables

Basic Assignment: Variables in Python are assigned values using the = operator.

x = 5
y = 3.14
z = "Hi"

Dynamic Typing: Python variables are dynamically typed, meaning the same variable can hold different types of values during execution.

x = 10
x = "Now a string"

Multiple Assignments

Assigning Same Value: Python allows assigning the same value to multiple variables in a single line, which can be useful for initializing variables with the same value.

a = b = c = 100

print(a, b, c)

100 100 100

Assigning Different Values: We can assign different values to multiple variables simultaneously, making the code concise and easier to read.