What does the `len()` function achieve in Python?

The len() function in Python is designed to return the number of items in an object, which may include strings, lists, tuples, dictionaries, and other iterable collections. When you pass an object to len(), it counts the number of elements contained in that object.

For example, if you have a string like "hello", using len("hello") will return 5, since there are five characters in the string. Similarly, for a list containing the numbers [1, 2, 3], len([1, 2, 3]) would return 3, reflecting the number of elements in the list. This makes len() a versatile function particularly useful for data structure manipulations, allowing users to quickly assess the size or length of containers in their programs.

This function is fundamental in programming as it helps in looping through objects, managing data, and performing checks before processing elements, thereby enhancing code efficiency and effectiveness.