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: Traffic lights

5. Recursion and Lambda Functions

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

Built-in Functions

Built-in functions in Python are predefined functions that are readily available for use in any Python program without requiring additional specifications or definitions. One of these built-in functions is the print() function, which we have already used. We didn't need to define this function, write its body, or specify the return value; we simply called it and provided inputs. There are many built-in functions in Python. Let's consider some of the most commonly used ones:

print(): Outputs a specified message or variable to the console.


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print("My message")

len(): Returns the number of elements in an object, such as a string, list, or tuple.


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word = "Codefinity"
print("Word length:", len(word))

sum(): Computes the total of a sequence of numbers.


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numbers = [5, 2, 3]
print("Sum of numbers:", sum(numbers))

max() and min(): Return the maximum or minimum value from a sequence.


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numbers = [5, 2, 3]
print("The largest among the numbers:", max(numbers))
print("The smallest of the numbers:", min(numbers))

You might already be familiar with these functions, or perhaps not. The key in this chapter is to understand the difference between built-in functions and those you create yourself.

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Section 1. Chapter 6