String 만지기

String.swift

import Foundation

let s = "Hello, World!"
print(s)

// string -> string array
var a = s.map { String($0) }
print(a)

// string array -> string
//let b = a.reduce("") { $0 + $1 }
let b = a.reduce("", +)
print(b)

extension String {
    func contains(s: String) -> Bool
    {
        return self.range(of: s) != nil ? true : false
    }
    func isMatch(pattern: String, options: NSRegularExpression.Options) -> Bool {
        let range = NSRange(location: 0, length: self.count)
        let regex = try! NSRegularExpression(pattern: pattern, options: options)
        let result = regex.matches(in: self, options: [], range: range)
        return result.count > 0
    }
    func getMatchesString(pattern: String, options: NSRegularExpression.Options) -> [String] {
        let range = NSRange(location: 0, length: self.count)
        let regex = try! NSRegularExpression(pattern: pattern, options: options)
        let result = regex.matches(in: self, options: [], range: range)
        return result.map { String(self[Range($0.range, in: self)!]) }
    }
    func getMatches(pattern: String, options: NSRegularExpression.Options) -> [NSTextCheckingResult] {
        let range = NSRange(location: 0, length: self.count)
        let regex = try! NSRegularExpression(pattern: pattern, options: options)
        let result = regex.matches(in: self, options: [], range: range)
        return result
    }
    subscript (at: Int) -> String
    {
        get {
            guard let s = index(startIndex, offsetBy: at, limitedBy: endIndex) else { return "" }
            guard let e = index(startIndex, offsetBy: at+1, limitedBy: endIndex) else { return "" }
            return String(self[s..<e])
        }
    }
    subscript (begin: Int, end: Int) -> String
    {
        get {
            guard let s = index(startIndex, offsetBy: begin, limitedBy: endIndex) else { return "" }
            guard let e = index(startIndex, offsetBy: end, limitedBy: endIndex) else { return String(self[s..<endIndex]) }
            return String(self[s..<e])
        }
    }
}

print(s.contains(s: "llo"))
print(s[0, 5])
print(s[100, 4])
print(s[4, 100])
print(s[4, 5])
print(s[4])

print(s.isMatch(pattern: "Hello", options: []))
print(s.getMatches(pattern: "[a-z]+", options: [])[1].range.location)
print(s.getMatches(pattern: "[a-z]+", options: [])[1].range.length)
print(s.getMatchesString(pattern: "[a-z]+", options: []))

print(s.replacingOccurrences(of: "World", with: "yap"))
print(s)

Hello, World!
["H", "e", "l", "l", "o", ",", " ", "W", "o", "r", "l", "d", "!"]
Hello, World!
true
Hello

o, World!
o
o
true
8
4
["ello", "orld"]
Hello, yap!
Hello, World!