iOS Swift. Rounding a double value to N number of decimal places

For round double values we can use classic algorithm of rounding. Add new function to Double class (with Extension):

import Foundation
import UIKit

extension Double {
    
    func roundToPlaces(places: Int) -> Double {
        let divisor = pow(10.0, Double(places))
        return (self * divisor).rounded() / divisor
    }
    
}

And we can use this extension for double variables:

let pi = 3.14159265
let roundedValue = pi.roundToPlaces(places: 2) // 3.14
print(roundedValue)