String 매서드, 프로퍼티

removeAll

Apple Developer Documentation

Apple Developer Documentation

var phrase = "The rain in Spain stays mainly in the plain."

let vowels: Set<Character> = ["a", "e", "i", "o", "u"]
phrase.removeAll(where: { vowels.contains($0) })
// phrase == "Th rn n Spn stys mnly n th pln."

enum HTTPResponse {
    case ok
    case error(Int)
}

let lastThreeResponses: [HTTPResponse] = [.ok, .ok, .error(404)]
let hadError = lastThreeResponses.contains { element in
    if case .error = element {
        return true
    } else {
        return false
    }
}
// 'hadError' == true

filter

: 특정 조건 만족하는 것만 뽑는 것

Apple Developer Documentation

let cast = ["Vivien", "Marlon", "Kim", "Karl"]
let shortNames = cast.filter { $0.count < 5 }
print(shortNames)
// Prints "["Kim", "Karl"]"

popLast

Apple Developer Documentation

firstIndex

Apple Developer Documentation

var students = ["Ben", "Ivy", "Jordell", "Maxime"]
if let i = students.firstIndex(of: "Maxime") {
    students[i] = "Max"
}
print(students)
// Prints "["Ben", "Ivy", "Jordell", "Max"]"

split

Apple Developer Documentation

let line = "BLANCHE:   I don't want realism. I want magic!"
print(line.split(whereSeparator: { $0 == " " }))
// Prints "["BLANCHE:", "I", "don\'t", "want", "realism.", "I", "want", "magic!"]"

print(line.split(maxSplits: 1, whereSeparator: { $0 == " " }))
// Prints "["BLANCHE:", "  I don\'t want realism. I want magic!"]"

print(line.split(omittingEmptySubsequences: false, whereSeparator: { $0 == " " }))
// Prints "["BLANCHE:", "", "", "I", "don\'t", "want", "realism.", "I", "want", "magic!"]"

reduce

Apple Developer Documentation

let numbers = [1, 2, 3, 4]
let numberSum = numbers.reduce(0, { x, y in
    x + y
})
// numberSum == 10

map

: 블락 안의 조건 만족도록 뽑는 것

Apple Developer Documentation

let cast = ["Vivien", "Marlon", "Kim", "Karl"]
let lowercaseNames = cast.map { $0.lowercased() }
// 'lowercaseNames' == ["vivien", "marlon", "kim", "karl"]
let letterCounts = cast.map { $0.count }
// 'letterCounts' == [6, 6, 3, 4]

forEach()

Apple Developer Documentation

let numberWords = ["one", "two", "three"]
for word in numberWords {
    print(word)
}
// Prints "one"
// Prints "two"
// Prints "three"

numberWords.forEach { word in
    print(word)
}
// Same as above

enumberated()

Apple Developer Documentation

for (n, c) in "Swift".enumerated() {
    print("\(n): '\(c)'")
}
// Prints "0: 'S'"
// Prints "1: 'w'"
// Prints "2: 'i'"
// Prints "3: 'f'"
// Prints "4: 't'"

sorted()

Apple Developer Documentation

let students: Set = ["Kofi", "Abena", "Peter", "Kweku", "Akosua"]
let descendingStudents = students.sorted(by: >)
print(descendingStudents)
// Prints "["Peter", "Kweku", "Kofi", "Akosua", "Abena"]"

index

Apple Developer Documentation

Apple Developer Documentation

Apple Developer Documentation

Apple Developer Documentation

var c = MyFancyCollection([10, 20, 30, 40, 50])
var i = c.startIndex
while i != c.endIndex {
    c[i] /= 5
    i = c.index(after: i)
}
// c == MyFancyCollection([2, 4, 6, 8, 10])