Sorted and custom comparators in Swift - Mini Project: Build & Apply

Sorting a List of Fruits with Custom Order in Swift

📖 Scenario: You have a list of fruits, but you want to sort them in a special order that you decide, not just alphabetically.

🎯 Goal: Build a Swift program that sorts a list of fruits using a custom order you define.

📋 What You'll Learn

Create an array called fruits with the exact values: "apple", "banana", "cherry", "date", "elderberry"

Create a dictionary called priority that assigns each fruit a number representing its custom order

Use the sorted(by:) method with a custom comparator closure to sort fruits by the priority values

Print the sorted array exactly as shown

💡 Why This Matters

🌍 Real World

Sorting items by custom rules is common in apps like shopping lists, games, or task managers where order matters beyond simple alphabetical sorting.

💼 Career

Understanding how to use custom comparators and sorting is important for software developers working on user interfaces, data processing, and any feature that requires ordered data.

1

Create the fruits array

Create an array called fruits with these exact string values in this order: "apple", "banana", "cherry", "date", "elderberry"

Swift

# Create the fruits array with the exact values
# Your code here

Need a hint?

Use square brackets [] to create an array and separate the fruit names with commas.

2

Create the priority dictionary

Create a dictionary called priority that assigns these exact values: "banana": 1, "apple": 2, "date": 3, "cherry": 4, "elderberry": 5

Swift

let fruits = ["apple", "banana", "cherry", "date", "elderberry"]
# Create the priority dictionary with the exact key-value pairs
# Your code here

Need a hint?

Use square brackets [] with key-value pairs separated by colons and commas.

3

Sort fruits using the custom priority

Create a new constant called sortedFruits that sorts fruits using sorted(by:) with a closure comparing the priority values of two fruits

Swift

let fruits = ["apple", "banana", "cherry", "date", "elderberry"]
let priority = ["banana": 1, "apple": 2, "date": 3, "cherry": 4, "elderberry": 5]
# Sort fruits using sorted(by:) with a closure comparing priority values
# Your code here

Need a hint?

Use fruits.sorted { priority[$0]! < priority[$1]! } to sort by priority values.

4

Print the sorted fruits

Print the sortedFruits array exactly using print(sortedFruits)

Swift

let fruits = ["apple", "banana", "cherry", "date", "elderberry"]
let priority = ["banana": 1, "apple": 2, "date": 3, "cherry": 4, "elderberry": 5]
let sortedFruits = fruits.sorted { priority[$0]! < priority[$1]! }
# Print the sortedFruits array
# Your code here

Need a hint?

Use print(sortedFruits) to show the sorted list.