How to Determine the Number of Elements in a Python List (Length of a List): A Comprehensive Guide

Python offers a powerful method for ascertaining the number of elements present within a list: the enigmatic len() function. This versatile tool can be employed with an array of data types, including both intrinsic Python types and those imported from external libraries.

Consider the following illustration:

items = ["apple", "orange", "banana"]

To delineate the precise quantity of elements within the items list, invoke the len() function:

>>> len(items)
3

Voilà! The output succinctly conveys that the items list harbors three distinct elements.

Underlying Mechanism of the len() Function

The len() function operates by scrutinizing the intrinsic attributes of its argument. Depending on the argument's nature, it retrieves the appropriate parameter that corresponds to its length or size:

• Lists, tuples, sets, and dictionaries: The count of their constituent elements
• Strings: The character count
• Other iterable objects: The number of iterations they can undergo