type alias

In Python, a type alias allows you to create an alternative name for an existing type. It’s a convenient way to make your type hints more readable.

You can create a type alias by assigning a type to a variable name. This is particularly useful when you have a complex type that you use frequently across your codebase. By using a type alias, you can refer to the complex type with a less complex and more descriptive name, enhancing code readability and maintainability.

Example

Here’s a quick example of how you can use a type alias in Python:

Python 
>>> Coordinate = tuple[float, float]
>>> Path = list[Coordinate]

>>> # Type hints with the type alias
>>> path: Path = [(1.0, 2.0), (2.0, 3.5), (5.0, 6.0)]

>>> # Type hints without the tupe alias
>>> path: list[tuple[float, float]] = [(1.0, 2.0), (2.0, 3.5), (5.0, 6.0)]

In this example, Coordinate is a type alias for a tuple containing two floating-point numbers, and Path is a type alias for a list of coordinates. This way, the code that uses type hints looks more readable and less complex.

The Ultimate Guide to Python Type Checking

Tutorial

Python Type Checking (Guide)

In this guide, you'll look at Python type checking. Traditionally, types have been handled by the Python interpreter in a flexible but implicit way. Recent versions of Python allow you to specify explicit type hints that can be used by different tools to help you develop your code more efficiently.

intermediate best-practices

For additional information on related topics, take a look at the following resources:

By Leodanis Pozo Ramos • Updated April 25, 2025
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