swift - Extension #3 (Adding Method)

Adding Method

extension Double {
    func toFahrenheit() -> Double {
        return self * 9 / 5 + 32
    }
    
    func toCelsius() -> Double {
        return (self - 32) * 5 / 9
    }
    
    static func converToFahrenheit(from celsius: Double) -> Double {
        return celsius.toFahrenheit()
    }
    
}

let c = 30.0
c.toFahrenheit()

Double.converToFahrenheit(from: 30.0)

extension Date {
    func toString(format: String = "yyyyMMdd") -> String {
        let privateFormatter = DateFormatter()
        privateFormatter.dateFormat = format
        return privateFormatter.string(from: self)
    }
}
let today = Date()
today.toString()
today.toString(format: "MM/DD/yyyy")

extension String {
    static func random(length: Int, charactersIn chars: String = "abcdefcgaeawgxgargaAFAEGSGRG") -> String {
        var randomString = String()
        randomString.reserveCapacity(length)
        
        for _ in 0 ..< length {
            guard let char = chars.randomElement() else {
                continue
            }
            randomString.append(char)
        }
        return randomString
    }
}

String.random(length: 5)