Of course! In Python, the keyword is False (with a capital 'F' and no quotes). It's a boolean value, one of the two built-in boolean types in Python (the other being True).

You use return False inside a function to send the boolean value False back to wherever the function was called.

Here’s a breakdown of what this means, why you'd do it, and common examples.

The Basics: return False vs. return "False"

This is a very common point of confusion.

• return False: Returns the boolean value False. This is used for logical checks.
• return "False": Returns the string "False". This is just a piece of text.

You should almost always use False (without quotes) when you are doing logical operations.

# This is what you usually want
def is_even(number):
  if number % 2 == 0:
    return True  # It's an even number
  else:
    return False # It's NOT an even number
# This is probably NOT what you want
def get_status_string():
  return "False" # This is just a string, not a logical value

Why Use return False?

The primary purpose of return False is to signal that a condition was not met or an operation failed. It's a way to communicate a "no" or "failure" status from a function.

Common Use Cases:

a) Checking for a Condition (Predicates) A function that returns True or False is often called a "predicate". You use it to ask a question about something.

def is_adult(age):
  """Checks if a person is an adult (18 or older)."""
  if age >= 18:
    return True
  return False # The else: is implied
# How to use it
age1 = 25
age2 = 16
if is_adult(age1):
  print(f"{age1} is an adult.")
else:
  print(f"{age1} is not an adult.")
if is_adult(age2):
  print(f"{age2} is an adult.")
else:
  print(f"{age2} is not an adult.")

Output:

25 is an adult.
16 is not an adult.

b) Searching for an Item A function might search through a list and return True if it finds the item, and False if it doesn't.

def find_item_in_list(item, my_list):
  """Searches for an item in a list."""
  for element in my_list:
    if element == item:
      return True # Found it!
  return False # Went through the whole list, didn't find it
# How to use it
groceries = ["milk", "eggs", "bread"]
item_to_find = "eggs"
item_not_found = "cereal"
if find_item_in_list(item_to_find, groceries):
  print(f"Yes, we have {item_to_find}.")
else:
  print(f"No, we don't have {item_to_find}.")
if find_item_in_list(item_not_found, groceries):
  print(f"Yes, we have {item_not_found}.")
else:
  print(f"No, we don't have {item_not_found}.")

Output:

Yes, we have eggs.
No, we don't have cereal.

c) Handling Errors or Invalid Input A function can perform an action and return False if it fails.

def divide_safely(a, b):
  """Divides two numbers safely. Returns False on division by zero."""
  if b == 0:
    print("Error: Cannot divide by zero.")
    return False # Signal that the operation failed
  result = a / b
  return result # Return the successful result
# How to use it
result1 = divide_safely(10, 2)
if result1 is not False: # Check if the operation was successful
  print(f"The result is: {result1}")
result2 = divide_safely(10, 0)
if result2 is not False:
  print(f"The result is: {result2}")

Output:

The result is: 5.0
Error: Cannot divide by zero.

What Happens if You Just return?

If you write a function with a return statement but don't give it a value, it implicitly returns None.

def check_password(password):
  if password == "secret123":
    return True # Explicitly returns True
  return # Implicitly returns None
# How to use it
result = check_password("wrongpass")
print(f"The function returned: {result}")
print(f"The type of the result is: {type(result)}")
# You can't use this in an `if` statement like you can with `False`
if result: # This check will fail for None, False, 0, empty sequences, etc.
  print("Password is correct!")
else:
  print("Password is incorrect.")

Output:

The function returned: None
The type of the result is: <class 'NoneType'>
Password is incorrect.

While if None: behaves similarly to if False: in an if statement, it's much clearer and more explicit to write return False if that's your intention.

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