Sequence Operators

Part of the Fundamentals section of Coddy's Swift journey — lesson 75 of 86.

Swift provides useful built-in properties and methods that let you quickly gather information about arrays without writing loops. These sequence operators help you perform common calculations with minimal code.

The count property returns the number of elements in an array:

let scores = [85, 92, 78, 90]
print(scores.count)  // 4

For numeric arrays, Swift offers methods to find the smallest and largest values. The min() and max() methods return optionals since an empty array has no minimum or maximum:

let temperatures = [72, 68, 75, 80, 65]

if let lowest = temperatures.min() {
    print(lowest)  // 65
}

if let highest = temperatures.max() {
    print(highest)  // 80
}

To calculate the total of all elements, use the reduce method. It combines all values starting from an initial value:

let prices = [10, 20, 30]
let total = prices.reduce(0, +)
print(total)  // 60

The 0 is the starting value, and + tells Swift to add each element to the running total. Combining these operators, you can easily calculate an average:

let grades = [85, 90, 78, 92]
let average = grades.reduce(0, +) / grades.count
print(average)  // 86

Challenge

Easy

Write a function analyzeScores that takes scores and returns a summary string with statistics about the array.

Use sequence operators to calculate the count, minimum, maximum, and average of the scores, then format them into a single summary string.

Logic:

Get the total count of elements using count
Find the minimum value using min()
Find the maximum value using max()
Calculate the sum using reduce(0, +) and divide by count to get the average
Return a formatted string with all statistics

Parameters:

scores ([Int]): An array of integer scores (guaranteed to have at least one element)

Returns: A formatted string containing the statistics (String). Format: "Count: X, Min: X, Max: X, Avg: X"

Example: If scores is [85, 90, 78, 92], the function should return "Count: 4, Min: 78, Max: 92, Avg: 86".

Note: The average should be calculated using integer division (no decimal places).

Cheat sheet

Swift provides built-in properties and methods for working with arrays without writing loops.

The count property returns the number of elements:

let scores = [85, 92, 78, 90]
print(scores.count)  // 4

The min() and max() methods find the smallest and largest values. They return optionals since empty arrays have no minimum or maximum:

let temperatures = [72, 68, 75, 80, 65]

if let lowest = temperatures.min() {
    print(lowest)  // 65
}

if let highest = temperatures.max() {
    print(highest)  // 80
}

The reduce method calculates the total by combining all values starting from an initial value:

let prices = [10, 20, 30]
let total = prices.reduce(0, +)
print(total)  // 60

Calculate an average by combining reduce with count:

let grades = [85, 90, 78, 92]
let average = grades.reduce(0, +) / grades.count
print(average)  // 86

Try it yourself

func analyzeScores(scores: [Int]) -> 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 Function String 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 2Sequence OperatorsThe Contains Method