A Beginner’s Guide to Type Hints in Python

Python is known for its simplicity and dynamic typing, which lets you write code without worrying about explicitly defining variable types. However, as projects grow, the lack of type annotations can lead to confusion, bugs, and reduced readability.

Enter type hints — a powerful feature introduced in Python 3.5 that allows developers to annotate the expected types of variables, function arguments, and return values. Type hints improve code clarity, make debugging easier, and empower tools like mypy to perform static type checks before the code runs.

In this post, we’ll explore the basics of type hints and how they can elevate your Python coding experience.

What Are Type Hints?

Type hints are optional annotations that specify the types of variables and function arguments. While they don’t enforce type checking at runtime, they act as a guide for developers and tools, making the code more understandable and error-resistant.

Syntax for Type Hints

1. Function Arguments and Return Types

You can specify the type of function arguments and use -> to indicate the return type:

def greet(name: str) -> str:
    return f"Hello, {name}!"