Print Function

Part of the Fundamentals section of Coddy's Swift journey — lesson 31 of 86.

You've been using print() throughout this course to display output. Now let's take a closer look at how this function works and explore some of its useful features.

By default, print() adds a newline character at the end of each output, which is why each print statement appears on its own line:

print("Hello")
print("World")
// Output:
// Hello
// World

You can change this behavior using the terminator parameter. This lets you specify what character (or string) should appear at the end instead of a newline:

print("Hello", terminator: " ")
print("World")
// Output: Hello World

The print() function can also accept multiple items separated by commas. By default, they're joined with spaces:

print("Swift", "is", "fun")
// Output: Swift is fun

You can customize the separator using the separator parameter:

print("2024", "01", "15", separator: "-")
// Output: 2024-01-15

Challenge

Easy

Write a function formatDate that takes year, month, and day and returns a formatted date string.

Use the print() function with the separator parameter to join the three date components with a hyphen (-), then capture the result to return it.

Hint: You can use print() with a custom separator to format the output, but since this function needs to return a string, you'll need to construct the formatted string directly by joining the components with "-".

Parameters:

year (String): The year value
month (String): The month value
day (String): The day value

Returns: A formatted date string with components joined by hyphens. Format: year-month-day

Cheat sheet

By default, print() adds a newline character at the end of each output:

print("Hello")
print("World")
// Output:
// Hello
// World

Use the terminator parameter to change what appears at the end instead of a newline:

print("Hello", terminator: " ")
print("World")
// Output: Hello World

The print() function accepts multiple items separated by commas, joined with spaces by default:

print("Swift", "is", "fun")
// Output: Swift is fun

Use the separator parameter to customize how items are joined:

print("2024", "01", "15", separator: "-")
// Output: 2024-01-15

Try it yourself

func formatDate(year: String, month: String, day: String) -> String {
    // Write code here
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Fundamentals

1Introduction

The Language Hello World!Comments

4Operators Part 1

Arithmetic Operators Modulo Operator Compound Assignment Recap - Simple Math Comparison Operators

7Basic IO

Print FunctionString Interpolation ReadLine Input Type Conversion Recap - Till 120 Recap - True or False

10Functions

Declare A Function Parameters And Arguments Return Values Argument Labels Recap - Sigma Function Recap - Validation Function Default Values

13Iterating Over Sequences

Iterating Over Elements The Enumerated Method Iterating Over Strings P1 Iterating Over Strings P2

16Final Challenges

Flat Asterisk Pyramid Pattern Finder What To Buy

2Variables

Let vs Var Type Annotations Numbers String Boolean Naming Conventions Recap - Initialize Variables

5Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3 Ternary Operator

8Bill Split Calculator

Welcome Message Getting Input

Calculating Tip And Total

Splitting The Bill

Formatted Output

11FizzBuzz with a Twist

Game Overview The FizzBuzz Function

Looping The Numbers

Adding The Twist

14Arrays Advanced

Array Slicing Part 1 Array Slicing Part 2 Sequence Operators The Contains Method