python type hints on module properties like Protocol for module смотреть онлайн

In Python, type hints provide a way to specify the expected types of variables, function parameters, and return values. While type hints are commonly used for functions and classes, they can also be applied to module-level properties and variables. This tutorial will focus on using type hints for module-level properties, including using the Protocol for module properties.
Type hints, introduced in PEP 484 and significantly expanded in PEP 526, allow you to specify the expected data types for variables, parameters, and return values. When you use type hints for module-level properties, you make your code more self-explanatory and enhance the development experience by providing hints to code editors and static analysis tools.
To use type hints for module-level properties, you can simply assign type annotations to the properties. Here's a basic example:
In this example, we've defined two module-level properties, my_variable and my_list, and provided type hints for both of them. The first property is of type int, and the second property is a list containing int elements.
You can also use custom classes or types as type hints for module properties:
In this example, we've created a Person class and defined a module-level property people as a list of Person objects.
In some cases, you may need to use protocols to specify the expected properties of module-level objects. Protocols allow you to declare the expected attributes and their types without creating a specific class. You can use the Protocol class from the typing module to define a protocol.
Here's an example of using a protocol for module properties:
In this example, we've defined an Employee protocol that specifies the expected attributes for an employee object. The employee_info module-level property is of type Employee, and it must have the name and employee_id attributes.
Let's put everything together in a complete example. We'll define a module with module-level properties, type hints, and a protocol:
In this example, we've defined my_integer as an integer, my_list as a list of integers, and my_person as a Person object. The greet_person function takes a Person object as a parameter and greets the person by name.
Type hints for module-level properties and protocols provide a powerful way to enhance code readability, maintainability, and collaboration in Python projects. By using type hints, you can communicate your code's intent clearly and enable code editors and static analysis tools to provide bett