[swift]data、int與string轉換

int to data：

//int to data
var num = -12300
let data = Data.init(bytes: &num, count: MemoryLayout.size(ofValue: num))
//        bytes : 8 elements
//          - 0 : 244
//          - 1 : 207
//          - 2 : 255
//          - 3 : 255
//          - 4 : 255
//          - 5 : 255
//          - 6 : 255
//          - 7 : 255

//data to int
let value = data.withUnsafeBytes {
		$0.load(as: Int.self)
}
print(value)
//        -12300
        
let value1 = data.withUnsafeBytes { UnsafeRawBufferPointer in
		UnsafeRawBufferPointer.load(as: Int.self)
}
print(value1)
//        -12300

string to data：

//string to data
let strData = "hello".data(using: .utf8, allowLossyConversion: true)!
//        bytes : 5 elements
//          - 0 : 104
//          - 1 : 101
//          - 2 : 108
//          - 3 : 108
//          - 4 : 111

int to string：

//int to string
let intStr = String(-1234)
print(intStr)

string to int：

//string to int
let strInt = Int(intStr)!
print(strInt)

data to string：

//data to string
let dataStr = String.init(data: strData, encoding: .utf8)!
print(dataStr)
//        hello