string_interpolation_performance_tests.swift

#!/usr/bin/swift
import Foundation

func measure(_ title: String, operation: () -> Void) {
    let closedRange = 0...4

    let averageTimeInSeconds = closedRange
        .map { _ ->  CFAbsoluteTime in
            let startTime = CFAbsoluteTimeGetCurrent()
            operation()
            return CFAbsoluteTimeGetCurrent() - startTime
        }
        .reduce(0.0, +) / Double(closedRange.count)

    print("Average time from 5 executions: `\(title)` => \(averageTimeInSeconds)s.")
}

let a = "I'm"
let b = "iOS"
let c = "Developer"

measure("string interpolation") {
    for _ in 0...99_999 {
        let _ = "\(a) an \(b) \(c)"
    }
}

measure("string concatenation") {
    for _ in 0...99_999 {
        let _ = a + " an " + b + " " + c
    }
}


measure("string concatenation using joined(separator:) function") {
    for _ in 0...99_999 {
        let _ = [a, b, "an", c].joined(separator: " ")
    }
}