Write a function named doubleNumber(_:) that takes in a Double and returns that number times two
//Your function here
// input: 99
// output: 198
// input: 3.0
// output: 6.0Solution
func double(_ number: Double) -> Double {
return number * 2
}
print(double(99)) // 198.0Write a function named smallest(of:and:) that takes in two Doubles and returns the smaller number. Don't use the built-in max() function.
// input: 2.3, 2.03
// output: 2.03
// input: 8.0, 3.0
// output: 3.0// Your function hereSolution
func smallest(of num1: Double, and num2: Double) -> Double {
let result = num1 < num2 ? num1 : num2
return result
}
print(smallest(of: 2.3, and: 2.03)) // 2.03
print(smallest(of: 8.0, and: 3.0)) // 3.0Write a function named smallestValue(in:) that takes in an array of Doubles and returns the smallest Double. Don't use .min()
// input: [1.0,2,3,4,5,5]
// output: 1.0
// input: [-4,-59,-348,-34,-4]
// output: -348Solution
func smallestValue(in arr: [Double]) -> Double {
guard var smallest = arr.first else { return 0 }
for num in arr {
if num < smallest {
smallest = num
}
}
return smallest
}
print(smallestValue(in: [1.0,2,3,4,5,5])) // 1.0
print(smallestValue(in: [-4,-59,-348,-34,-4])) // -348Write a function named occurrences(of:in:) that counts how many Characters in a String match a specific character.
// input: "hello", "l"
// output: 2
// input: "Now with some spaces", " "
// output: 3Solution
func occurrences(of char: Character, in str: String) -> Int {
let characters = str.filter { $0 == char }
return characters.count
}
print(occurrences(of: "l", in: "hello")) // 2
print(occurrences(of: " ", in: "Now with some spaces")) // 3Write a function called removeNils(from:) that takes an array of optional Ints and returns an array with them unwrapped with any nil values removed.
// input: [1, nil, 9, nil, 10, nil]
// output: [1, 9, 10]
// input: [1, 2, 3]
// output: [1, 2, 3]
// input: [nil]
// output: []
// input: []
// output: []// Your function hereSolution
func removeNils(from arr: [Int?]) -> [Int] {
let results = arr.compactMap { $0 }
return results
}
print(removeNils(from: [1, nil, 9, nil, 10, nil])) // [1, 9, 10]
print(removeNils(from: [1, 2, 3])) // [1, 2, 3]
print(removeNils(from: [nil])) // []
print(removeNils(from: [])) // []Write a function named average(of:) that returns the average of an array of Doubles.
// input: [1,2,3,4,5]
// output: 3
// input: [1.5, 2.25, 4.5, -1.5]
// output: 1.6875Solution
func average(of numbers: [Double]) -> Double {
let results = numbers.reduce(0.0, +)
return results / Double(numbers.count)
}
print(average(of: [1,2,3,4,5])) // 3
print(average(of: [1.5, 2.25, 4.5, -1.5])) // 1.6875Write a function named frequencyDictionary(of:) that takes a String as input and returns a dictionary that maps each Character to its number of occurrances.
// input: "hello"
// output: ["h": 1, "e": 1, "l": 2, "o": 1]
// input: "aaaaaAAA"
// output: ["a": 5, "A":3]
// input: "More words"
// output: ["M": 1, "o": 2, "r": 2, "e": 1, " ": 1, "w": 1, "d": 1, "s": 1]Solution
func frequencyDictionary(of str: String) -> [Character: Int] {
var dict = [Character: Int]()
for char in str {
if let count = dict[char] {
dict[char] = count + 1
} else {
dict[char] = 1
}
}
return dict
}
print(frequencyDictionary(of: "hello")) // ["o": 1, "l": 2, "e": 1, "h": 1]
print(frequencyDictionary(of: "aaaaaAAA")) // ["a": 5, "A": 3]
print(frequencyDictionary(of: "More words")) // ["o": 2, " ": 1, "w": 1, "d": 1, "M": 1, "r": 2, "e": 1, "s": 1]Write a function named value(_:isGreaterThanAverageOf:) that takes in an array of Doubles and a Double and returns whether the Double is greater than the average.
// input: 4.0, [1.0,2,3,4,5]
// output: true
// input: 3, [1,2,3,4,5]
// output: false
// input: 100.8, [1,42,1,541,42,5]
// output: false // Your function hereSolution
func value(_ num: Double, isGreaterThanAverageOf numbers: [Double]) -> Bool {
let average = numbers.reduce(0.0, +) / Double(numbers.count)
let result = num > average ? true : false
return result
}
print(value(4.0, isGreaterThanAverageOf: [1.0,2,3,4,5])) // true
print(value(3, isGreaterThanAverageOf: [1,2,3,4,5])) // false
print(value(100.8, isGreaterThanAverageOf: [1,42,1,541,42,5])) // falseWrite a function that finds the second smallest Int an an array of Ints
// input: [1, 2, 3, 4]
// output: 2
// input: [2, 1, 3, 4]
// output: 2// Your function hereSolution
func secondSmallest(of numbers: [Int]) -> Int {
guard var smallest = numbers.first else { return 0 }
var secondSmallest = Int.max
for num in numbers {
if num < smallest {
secondSmallest = smallest
smallest = num
}
else if num < secondSmallest && num != smallest {
secondSmallest = num
}
}
return secondSmallest
}
print(secondSmallest(of: [1, 2, 3, 4])) // 2
print(secondSmallest(of: [2, 1, 3, 4])) // 2Write a program that outputs the string representation of numbers from 1 to n.
But for multiples of three it should output “Fizz” instead of the number and for the multiples of five output “Buzz”. For numbers which are multiples of both three and five output “FizzBuzz”.
// Example
/*
n = 15,
Return:
[
"1",
"2",
"Fizz",
"4",
"Buzz",
"Fizz",
"7",
"8",
"Fizz",
"Buzz",
"11",
"Fizz",
"13",
"14",
"FizzBuzz"
]
*/Solution
func fizzBuzz(_ n: Int) -> [String] {
var arr = [String]()
for i in 1...n {
if i % 3 == 0 && i % 5 == 0 {
arr.append("FizzBuzz")
}
else if i % 3 == 0 {
arr.append("Fizz")
}
else if i % 5 == 0 {
arr.append("Buzz")
}
else {
arr.append(i.description)
}
}
return arr
}
print(fizzBuzz(9)) // ["1", "2", "Fizz", "4", "Buzz", "Fizz", "7", "8", "Fizz"]
print(fizzBuzz(15)) // ["1", "2", "Fizz", "4", "Buzz", "Fizz", "7", "8", "Fizz", "Buzz", "11", "Fizz", "13", "14", "FizzBuzz"]