Type Conversion & Type Hinting in Python

Type Casting in Python

Type casting in Python refers to converting one data type into another. It's useful when you need to operate on values of different types in a compatible way.

Types of Type Casting

There are two main types:

1. Implicit Type Casting

2. Explicit Type Casting

1. Implicit Conversion

Python automatically converts data types.

a = 5
b = 2.0
c = a + b
print(c)
print(type(c))

Output:

7.0
<class 'float'>

2. Explicit Conversion (Type Casting)

You manually convert data using functions like int(), float(), str(), etc.

a = "10"
b = int(a)
c = float(a)

print(b, type(b))
print(c, type(c))

Output

10 <class 'int'>
10.0 <class 'float'>

Common Conversion Functions:

TYPE HINTING (Introduced in Python 3.5+)

Type hinting allows you to declare the expected data types of variables, function arguments, and return values. It helps improve code readability, debugging, and editor support.

Example 1: Function With Type Hints

def greet(name: str) -> str:
    return "Hello " + name

print(greet("Alice"))

Output:

Hello Alice

Example 2: Variable Type Hints

age: int = 25
pi: float = 3.14
active: bool = True

Example 3: Complex Function

def add_numbers(a: int, b: int) -> int:
    return a + b

print(add_numbers(3, 4))

Output:

7

Benefits of Type Hinting

Combining Type Hints with Default Values

def welcome(name: str = "Guest") -> str:
    return f"Welcome, {name}!"

print(welcome())

Output:

Welcome, Guest!

SUMMARY