typing.List()
TypingType hint for a list containing elements of type X. In Python 3.9+, use list[X] directly.
Signature
List[X]
Returns
type aliasExample
from typing import List
def process(items: List[str]) -> List[int]:
return [len(s) for s in items]About typing.List()
typing.List is a Python typing function with the signature List[X]. Type hint for a list containing elements of type X. In Python 3.9+, use list[X] directly. It returns a value of type type alias.
Python provides a rich set of built-in functions and standard library modules that cover common programming tasks. Understanding these functions helps you write more idiomatic, efficient Python code. The typing.Listfunction is commonly used in data processing, web development, scripting, and automation tasks.
When working with typing.List(), consider edge cases like empty inputs, None values, and type mismatches. Python's duck typing means many built-in functions work with any object that implements the required protocol (e.g., __len__ for len(), __iter__ for iteration). This flexibility is a key strength of Python's design philosophy.