Round up double to 2 decimal places

Question

How do I round up currentRatio to two decimal places?

let currentRatio = Double (rxCurrentTextField.text!)! / Double (txCurrentTextField.text!)! railRatioLabelField.text! = "\(currentRatio)" 

Answer 1

Use a format string to round up to two decimal places and convert the double to a String:

let currentRatio = Double (rxCurrentTextField.text!)! / Double (txCurrentTextField.text!)! railRatioLabelField.text! = String(format: "%.2f", currentRatio) 

Example:

let myDouble = 3.141 let doubleStr = String(format: "%.2f", myDouble) // "3.14" 

If you want to round up your last decimal place, you could do something like this (thanks Phoen1xUK):

let myDouble = 3.141 let doubleStr = String(format: "%.2f", ceil(myDouble*100)/100) // "3.15" 

Answer 2

(Swift 4.2 Xcode 11) Simple to use Extension:-

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

Use:-

if let distanceDb = Double(strDistance) {    cell.lblDistance.text = "\(distanceDb.round(to:2)) km" }