Ditch These 7 Bad Habits in Python https://jerrynsh.com/ditch-these-7-habits-from-your-python/

add_book.py

def add_book(book_id, storage=[]):
    storage.append(book_id)
    return storage

my_book_list = add_book(1)
print(my_book_list)

my_other_book_list = add_book(2)
print(my_other_book_list)

# Expectation:
# [1]
# [2]

# Reality:
# [1]
# [1, 2] Huh, what? But they are different variables!

add_book2.py

# Do:
def add_book(book_id, storage=None):
    if storage is None:
        storage = []
        
    storage.append(book_id)
    return storage

bare_except.py

# Do NOT ever use bare exception:
while True:
    try:
        input_string = input("Input something")
        converted_input = int(input_string)
        print(converted_input)
    
    except: # Can't do Ctrl + C to exit!
        print("Not a number!")

equality.py

# NOTE: In Python everything is an object, including list
listA = [1, 2, 3]
listB = [1, 2, 3]

listA is listB # False because they are NOT the same actual object
listA == listB # True because they are equivalent

equality2.py

# Do:
if foo is None:
    ...

# Don't:
if foo == None:
    ...

# Do:
if not bar:
    ...

# Don't:
if bar == False:
    ...

# Do:
if baz:
    ...

# Don't:
if baz is True:
    ...

# Don't
if baz == True:
    ...

list_comprehension.py

# Don't:
def generate_fruit_basket(fruits):
    """Without list comprehension"""
    basket = []
    for fruit in fruits:
        if fruit != "grapes":
            basket.append(fruit)

# Do:
def generate_fruit_basket_lc(fruits):
    """With list comprehension"""
    return [fruit for fruit in fruits if fruit != "grapes"]

list_comprehension2.py

# Don't:
def get_book_price(inventory):
    return [(book, price) for book in inventory if book.startswith('A') for price in inventory[book] if price > 10]

# Perhaps slightly better...? But please don't.
def get_book_price(inventory):
    return [
        (book, price) for book in inventory
        if book.startswith('A')
        for price in inventory[book]
        if price > 10
    ]