Scrivere una docstring

Hai deciso di creare il più grande pacchetto Python open source per il Natural Language Processing. Rivoluzionerà il lavoro con il testo libero, proprio come numpy ha fatto per gli array, pandas per i dati tabellari e scikit-learn per il machine learning.

La prima funzione che scrivi è count_letter(). Riceve una stringa e una singola lettera e restituisce il numero di volte in cui la lettera appare nella stringa. Vuoi che chi usa il tuo pacchetto open source capisca facilmente come funziona questa funzione, quindi devi fornirle una docstring. Costruisci una docstring in stile Google per questa funzione seguendo questi passaggi.

Questo esercizio fa parte del corso

Scrivere funzioni in Python

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Esercizio pratico interattivo

Prova a risolvere questo esercizio completando il codice di esempio.

# Add a docstring to count_letter()
def count_letter(content, letter):
  ____
  if (not isinstance(letter, str)) or len(letter) != 1:
    raise ValueError('`letter` must be a single character string.')
  return len([char for char in content if char == letter])

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: Docstring Exercise 2: Scrivere una docstring

Esercizio in corso

Exercise 3: Recuperare le docstring Exercise 4: Docstring, salvaci tu!Exercise 5: DRY e "Fai una sola cosa"Exercise 6: Estrai una funzione Exercise 7: Dividi una funzione Exercise 8: Passaggio per assegnazione Exercise 9: Mutabile o immutabile?Exercise 10: Buone pratiche per gli argomenti di default

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: Functions are objects Exercise 2: Building a command line data app Exercise 3: Reviewing your co-worker's code Exercise 4: Returning functions for a math game Exercise 5: Scope Exercise 6: Understanding scope Exercise 7: Modifying variables outside local scope Exercise 8: Closures Exercise 9: Checking for closure Exercise 10: Closures keep your values safe Exercise 11: Decorators Exercise 12: Using decorator syntax Exercise 13: Defining a 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!