Python Academy · Lesson

Functions as First-Class Objects

Understand closures and passing functions as arguments.

Introduction

In Python, functions are first-class objects: they can be passed as arguments, returned, and stored in data structures.

def double(x): return x*2 creates a function object. double is just a name. You can assign it: fn = double; fn(5) works.

def double(x): return x * 2
fn = double
print(fn(5))
print(type(fn))