Easily Implementing Python Type Hints in Lists/Tuples
How to Use Type Hints for Multiple Return Types in Python
Use Python’s Type Hints for One Piece of Data of Alternative Types
In Python, type hinting is an optional yet useful feature to make your code easier to read, reason about, and debug. With type hints, you let other developers know the expected data types for variables, function arguments, and return values. As you write code for applications that require greater flexibility, you may need to specify multiple return types to make your code more robust and adaptable to different situations.
You’ll encounter different use cases where you may want to annotate multiple return types within a single function in Python. In other words, the data returned can vary in type. In this tutorial, you’ll walk through examples of how to specify multiple return types for a function that parses a string from an email address to grab the domain name.
Conditional Statements
When a function uses conditional statements that return different types of results, you can convey this by specifying alternative return types for your function using type hints.
In the example above, the parse_email
function takes a string email
as an argument and returns either a string (the domain name) or None
, depending on whether the string contains an @
symbol or not.
Optional Values
A function may sometimes return no value, in which case you can use type hints to signal the occasional absence of a return value.
In the example above, the divide
function takes two integers a
and b
as arguments and returns either a float (the result of dividing a
by b
) or None
, if b
is equal to 0.
Error Handling
When a function encounters an error, you may want to return a specific error object that’s different from the normal results’ return type. Doing so could help other developers handle errors in the code.
In the example above, the process_data
function takes a string data
as an argument and returns either a string (the uppercase version of data
) or a ValueError
object, if the length of data
is less than or equal to 10.
Flexibility
When designing and writing code, you generally want it to be versatile, flexible, and reusable. This could mean writing functions that can handle a range of data types. Specifying this in type hints helps other developers understand your code’s versatility and its intended uses in different cases.
In the example above, the add_numbers
function takes two arguments a
and b
, which can be either integers or floats, and returns the sum of a
and b
, which can also be either an integer or a float.
Conclusion
Type hints in Python allow you to specify the expected data types for variables, function arguments, and return values, making your code more readable and maintainable. When dealing with multiple return types in a function, you can use type hints to convey this variability, helping other developers understand and use your code effectively. By using type hints effectively, you can write more robust and adaptable code in Python.