Convert Int to String in Swift

**Swift 4**:

let x:Int = 45
let str:String = String(describing: x)

[Developer.Apple.com > String > init(describing:)][2]

> The String(describing:) initializer is the preferred way to convert an instance of any type to a string.

[Custom String Convertible][3]

[![enter image description here][1]][1]



[1]:

[2]:

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[3]:

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If you like swift extension, you can add following code

extension Int
{
var string:String {
get {
return String(self)
}
}
}
then, you can get string by the method you just added

var x = 1234
var s = x.string

let intAsString = 45.description // "45"
let stringAsInt = Int("45") // 45

**Swift String performance**

A little bit about performance
`UI Testing Bundle` on iPhone 7(real device) with iOS 14
```
let i = 0
lt result1 = String(i) //0.56s 5890kB
lt result2 = "\(i)" //0.624s 5900kB
lt result3 = i.description //0.758s 5890kB
```

``` Swift
import XCTest

class ConvertIntToStringTests: XCTestCase {
let count = 1_000_000

func measureFunction(_ block: () -> Void) {
let metrics: [XCTMetric] = [
XCTClockMetric(),
XCTMemoryMetric()
]
let measureOptions = XCTMeasureOptions.default
measureOptions.iterationCount = 5

measure(metrics: metrics, options: measureOptions) {
block()
}
}

func testIntToStringConstructor() {
var result = ""
measureFunction {
for i in 0...count {
result += String(i)
}
}
}

func testIntToStringInterpolation() {
var result = ""
measureFunction {
for i in 0...count {
result += "\(i)"
}
}
}

func testIntToStringDescription() {
var result = ""
measureFunction {
for i in 0...count {
result += i.description
}
}
}
}
```