Functions in Python can be nested inside other functions.
A function defined inside a function is visible only inside that function.
This is useful to create utilities that are useful to a function, but not useful outside of it.
You might ask: why should I be “hiding” this function, if it does not harm?
One, because it’s always best to hide functionality that’s local to a function, and not useful elsewhere.
Also, because we can make use of closures (more on this later).
Here is an example:
def talk(phrase): def say(word): print(word) words = phrase.split(' ') for word in words: say(word) talk('I am going to buy the milk')
If you want to access a variable defined in the outer function from the inner function, you first need to declare it as
def count(): count = 0 def increment(): nonlocal count count = count + 1 print(count) increment() count()
This is useful especially with closures, as we’ll see later.
More python tutorials:
- Introduction to Python
- Installing Python 3 on macOS
- Running Python programs
- Python 2 vs Python 3
- The basics of working with Python
- Python Data Types
- Python Operators
- Python Strings
- Python Booleans
- Python Numbers
- Python, Accepting Input
- Python Control Statements
- Python Lists
- Python Tuples
- Python Sets
- Python Dictionaries
- Python Functions
- Python Objects
- Python Loops
- Python Modules
- Python Classes
- The Python Standard Library
- Debugging Python
- Python variables scope
- Python, accept arguments from command line
- Python Recursion
- Python Nested Functions
- Python Lambda Functions
- Python Closures
- Python Virtual Environments
- Use a GoPro as a remote webcam using Python
- Python, how to create a list from a string
- Python Decorators
- Python Docstrings
- Python Introspection
- Python Annotations
- Python, how to list files and folders in a directory
- Python, how to check if a number is odd or even
- Python, how to get the details of a file
- Python, how to check if a file or directory exists
- Python Exceptions