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

Arguments

In Python, function arguments are the inputs you provide to a function when you call it. They allow you to supply data or values that the function can utilize. These arguments can be individual values or objects like lists, tuples, dictionaries, or custom objects.

For example, when we use the print() function, we provide a string as an argument. Here's another example:

Suppose we want to write a function that calculates the sum of two different numbers and prints the result. To achieve this, we need to pass these two numbers to the function using parentheses ().


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# Specify two arguments of the function
def sum_of_two_numbers(num_1, num_2):
	# Use arguments to calculate sum
	result = num_1 + num_2
    # Print the result
	print(f'Sum of two numbers is {result}')
 
# Call the function 
sum_of_two_numbers(2, 10)

We have passed num_1 and num_2 as arguments to the function and then used them to calculate the sum. You can set an arbitrary number of function arguments.

Let's consider an example where we use a list as an argument for the function:


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# Define the function `calculate_list_sum`
def calculate_list_sum(list):
    # Initialize the total sum to 0
    total = 0
    # Iterate through each number in the list
    for num in list:
        # Add the current number to the total sum
        total += num
    # Print the total sum
    print(total)

# Create a list of numbers
my_list = [1, 2, 3, 4, 5]
# Call the function 
calculate_list_sum(my_list)

This code defines a function calculate_list_sum that takes a list of numbers, calculates their sum by adding each number to the total variable, and prints the result. The function is called with the list my_list, containing the numbers [1, 2, 3, 4, 5], and outputs the sum, which is 15.

Task

Swipe to start coding

Assume that you have to calculate perimeter of the triangle with sides a, b and c.

Pass three arguments: a, b, and c to the function calculate_triangle_perimeter.
In the function, calculate the perimeter by adding the three sides together.

Solution

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Section 1. Chapter 3

Arguments

For example, when we use the print() function, we provide a string as an argument. Here's another example:


              123456789
            
# Specify two arguments of the function
def sum_of_two_numbers(num_1, num_2):
	# Use arguments to calculate sum
	result = num_1 + num_2
    # Print the result
	print(f'Sum of two numbers is {result}')
 
# Call the function 
sum_of_two_numbers(2, 10)

We have passed num_1 and num_2 as arguments to the function and then used them to calculate the sum. You can set an arbitrary number of function arguments.

Let's consider an example where we use a list as an argument for the function:


              123456789101112131415
            
# Define the function `calculate_list_sum`
def calculate_list_sum(list):
    # Initialize the total sum to 0
    total = 0
    # Iterate through each number in the list
    for num in list:
        # Add the current number to the total sum
        total += num
    # Print the total sum
    print(total)

# Create a list of numbers
my_list = [1, 2, 3, 4, 5]
# Call the function 
calculate_list_sum(my_list)

Task

Swipe to start coding

Assume that you have to calculate perimeter of the triangle with sides a, b and c.

Pass three arguments: a, b, and c to the function calculate_triangle_perimeter.
In the function, calculate the perimeter by adding the three sides together.

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 1. Chapter 3

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