for in vs. .map

for in vs .map.swift

// the code below uses a for in loop to create a new array named scoreAfterBonus where every element in scores gets a 10% bonus

var scoresAfterBonus: [Double] = []
for score in scores {
    scoresAfterBonus.append(Double(score) * 1.1)
}

// the code below uses the .map method to do the same thing with just one line. Also note that the array scoresAfterBonus can even be created as a constant if it’s not going to change in the future. Note another array tenPerentScores is created below to demonstrate that it can be created as a constant with let, impossible in the for loop which needs to change the array with each iterration using .append
let tenPercentScores = scores.map { Double($0) * 1.1 }