Course Content

Python Functions Tutorial

1. What is a Function in Python?

What Is Function?Challenge: Building Functions Arguments Return Value Function Body Built-in Functions

2. Positional and Optional Arguments

Positional Arguments Challenge: Positional Arguments Optional Arguments Challenge: Optional Arguments

3. Arbitrary Arguments

Arbitrary Arguments Arbitrary Keyword Arguments Combination of Positional and Optional Arguments

4. Function Return Value Specification

Single Return Value Multiple Return Values None Return Value Generator Functions Challenge: Automated Bus Announcements

5. Recursion and Lambda Functions

Recursion Challenge: Recursive File Search Lambda Functions Immediately Invoked Lambda Expression Writing Effective and Maintainable Functions

Multiple Return Values

Sometimes it's necessary to return multiple objects as a result of the function. We can do it using two different approaches:

Using a List or Tuple

We can create a list or tuple that contains all necessary objects inside the function and return it as a result of the function.


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# Define a function
def return_multiple_objects():
    obj1 = 'Hello'
    obj2 = 42
    obj3 = [1, 2, 3]
	# Return all objects packed into list
    return [obj1, obj2, obj3]
  
# Get the list with corresponding objects
result_list = return_multiple_objects()
for obj in result_list:
	print(obj)

We created three different objects inside the function and returned the list that contains all these objects as an output of the function. Then we iterated this list to get all objects.

Using Multiple Return Values

You can directly return multiple values separated by commas. When function is called, the results are captured in separate variables.


              12345678910
            
def return_multiple_objects():
    obj1 = "Hello"
    obj2 = 42
    obj3 = [1, 2, 3]
	# Return objects separated by comma
    return obj1, obj2, obj3

# Get the result of the function into three different values
result1, result2, result3 = return_multiple_objects()
print(result1, result2, result3)

In the code above we returned three variables separately. If we use this approach it's very important to know the order in which the variables are returned to correctly use them in code.

Task

Swipe to start coding

Implement a validate_registration function that validates user registration details by checking the username, email, and password. If any validation rule is not met, the function should return a list of error messages. Otherwise, it should confirm successful validation.

Define the function validate_registration, which takes three parameters: username, email, password
Initialize an empty list errors to store validation error messages.
Check if the username is at least 3 characters long. If not, add "Username must be at least 3 characters long." to the errors list.
Verify that the email contains the @ symbol. If not, add "Invalid email format." to the errors list.
Check if the password is at least 6 characters long. If not, add "Password must be at least 6 characters long." to the errors list.
Return the result of comparing the length of errors to 0 as the first parameter and the errors list as the second parameter.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 2

Multiple Return Values

Sometimes it's necessary to return multiple objects as a result of the function. We can do it using two different approaches:

Using a List or Tuple

We can create a list or tuple that contains all necessary objects inside the function and return it as a result of the function.


              123456789101112
            
# Define a function
def return_multiple_objects():
    obj1 = 'Hello'
    obj2 = 42
    obj3 = [1, 2, 3]
	# Return all objects packed into list
    return [obj1, obj2, obj3]
  
# Get the list with corresponding objects
result_list = return_multiple_objects()
for obj in result_list:
	print(obj)

We created three different objects inside the function and returned the list that contains all these objects as an output of the function. Then we iterated this list to get all objects.

Using Multiple Return Values

You can directly return multiple values separated by commas. When function is called, the results are captured in separate variables.


              12345678910
            
def return_multiple_objects():
    obj1 = "Hello"
    obj2 = 42
    obj3 = [1, 2, 3]
	# Return objects separated by comma
    return obj1, obj2, obj3

# Get the result of the function into three different values
result1, result2, result3 = return_multiple_objects()
print(result1, result2, result3)

In the code above we returned three variables separately. If we use this approach it's very important to know the order in which the variables are returned to correctly use them in code.

Task

Swipe to start coding

Define the function validate_registration, which takes three parameters: username, email, password
Initialize an empty list errors to store validation error messages.
Check if the username is at least 3 characters long. If not, add "Username must be at least 3 characters long." to the errors list.
Verify that the email contains the @ symbol. If not, add "Invalid email format." to the errors list.
Check if the password is at least 6 characters long. If not, add "Password must be at least 6 characters long." to the errors list.
Return the result of comparing the length of errors to 0 as the first parameter and the errors list as the second parameter.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 2

Switch to desktop for real-world practiceContinue from where you are using one of the options below