Python functions

The Python filter() Function

The Python filter() function provides a concise way to filter elements from an iterable based on a specified condition, returning an iterator of the true elements. Its syntax involves passing a function and an iterable object. The function can be a lambda expression or a defined function. The function tests each element and returns true or false based on the specified condition. If the function argument is set to None, filter() returns truthy elements of the iterable. Using filter() provides a more readable and concise approach for filtering elements compared to list comprehensions or loops.

The Python reduce() Function

The Python reduce() function aggregates elements in an iterable iteratively, accumulating a single result. It simplifies code involving iterative aggregation, providing a concise alternative to traditional loops. The basic syntax involves passing a function and an iterable, with an optional initial value. It’s powerful but not always necessary due to built-in functions like sum() and multiply().

Python Inner Functions

Python inner functions, also known as nested functions, are functions defined within the scope of another function. Inner functions are particularly useful as helper functions, which encapsulate logic only useful within the context of another function, and as factory functions, which create and return other more specialized functions.