Le closure mantengono al sicuro i tuoi valori

Stai ancora aiutando tua nipote a capire le closure. Hai scritto la funzione get_new_func() che restituisce una funzione annidata. La funzione annidata call_func() chiama qualunque funzione sia stata passata a get_new_func(). Hai anche scritto my_special_function() che semplicemente stampa un messaggio che indica che stai eseguendo my_special_function().

Vuoi mostrare a tua nipote che, indipendentemente da ciò che fai a my_special_function() dopo averla passata a get_new_func(), la nuova funzione continua a imitare il comportamento dell'originale my_special_function() perché si trova nella closure della nuova funzione.

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Scrivere funzioni in Python

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Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

def my_special_function():
  print('You are running my_special_function()')
  
def get_new_func(func):
  def call_func():
    func()
  return call_func

new_func = get_new_func(my_special_function)

# Redefine my_special_function() to just print "hello"
def my_special_function():
  ____

new_func()

Modifica ed esegui il codice

Questo esercizio fa parte del corso

Scrivere funzioni in Python

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The goal of this course is to transform you into a Python expert, and so the first chapter starts off with best practices when writing functions. You'll cover docstrings and why they matter and how to know when you need to turn a chunk of code into a function. You will also learn the details of how Python passes arguments to functions, as well as some common gotchas that can cause debugging headaches when calling functions.

Exercise 1: Docstrings Exercise 2: Crafting a docstring Exercise 3: Retrieving docstrings Exercise 4: Docstrings to the rescue!Exercise 5: DRY and "Do One Thing"Exercise 6: Extract a function Exercise 7: Split up a function Exercise 8: Pass by assignment Exercise 9: Mutable or immutable?Exercise 10: Best practice for default arguments

If you've ever seen the "with" keyword in Python and wondered what its deal was, then this is the chapter for you! Context managers are a convenient way to provide connections in Python and guarantee that those connections get cleaned up when you are done using them. This chapter will show you how to use context managers, as well as how to write your own.

Exercise 1: Using context managers Exercise 2: The number of cats Exercise 3: The speed of cats Exercise 4: Writing context managers Exercise 5: The timer() context manager Exercise 6: A read-only open() context manager Exercise 7: Advanced topics Exercise 8: Context manager use cases Exercise 9: Scraping the NASDAQ Exercise 10: Changing the working directory

Decorators are an extremely powerful concept in Python. They allow you to modify the behavior of a function without changing the code of the function itself. This chapter will lay the foundational concepts needed to thoroughly understand decorators (functions as objects, scope, and closures), and give you a good introduction into how decorators are used and defined. This deep dive into Python internals will set you up to be a superstar Pythonista.

Exercise 1: Le funzioni sono oggetti Exercise 2: Creare un'app dati da riga di comando Exercise 3: Revisionare il codice del tuo collega Exercise 4: Restituire funzioni per un gioco di matematica Exercise 5: Ambito Exercise 6: Capire lo scope Exercise 7: Modificare variabili fuori dallo scope locale Exercise 8: Closure Exercise 9: Verificare la closure Exercise 10: Le closure mantengono al sicuro i tuoi valori

Esercizio in corso

Exercise 11: Decorator Exercise 12: Usare la sintassi dei decorator Exercise 13: Definire un decorator

Now that you understand how decorators work under the hood, this chapter gives you a bunch of real-world examples of when and how you would write decorators in your own code. You will also learn advanced decorator concepts like how to preserve the metadata of your decorated functions and how to write decorators that take arguments.

Exercise 1: Real-world examples Exercise 2: Print the return type Exercise 3: Counter Exercise 4: Decorators and metadata Exercise 5: Preserving docstrings when decorating functions Exercise 6: Measuring decorator overhead Exercise 7: Decorators that take arguments Exercise 8: Run_n_times()Exercise 9: HTML Generator Exercise 10: Timeout(): a real world example Exercise 11: Tag your functions Exercise 12: Check the return type Exercise 13: Great job!