Rounding of floats to 2 decimals

Question

Hi guys, I'm a complete noob when it comes to Swift but I would appreciate any help.

The input value is set to be a float, but when displaying the calc results, I need it to be decimal style AND rounded up to the nearest 0.01.

It currently rounds off to the nearest 3 decimals, but I need it to be two decimals.

My code currently:

func roundUp(number: Float, toNearest: Float) -> Float {

return ceil(number / toNearest) * toNearest

}

let income = grossin - LocalGrossIncomeArray[5] + IntrestSAArray[3] - LocalGrossIncomeArray[9] - LocalGrossIncomeArray[8]

roundUp(income, toNearest: 0.1)

print("Income Round up value = \(income)")

roundUp(grossin, toNearest: 0.1)

print("grossin Round up value = \(grossin)")

let numberFormatterIncome = NSNumberFormatter()

numberFormatterIncome.numberStyle = .DecimalStyle

IncomeLbl.text = "R "

IncomeLbl.text = IncomeLbl.text! + numberFormatterIncome.stringFromNumber(income)!

let numberFormatter = NSNumberFormatter()

numberFormatter.numberStyle = .DecimalStyle

GrossIncome.text = "R "

GrossIncome.text = GrossIncome.text! + numberFormatter.stringFromNumber(Double(grossin))!

Swift

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Posted by

Dan_Scott_ZA

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Answer 1

It sounds like you’re working with currencies. If so, you should check out NSDecimalNumber, which is a fixed point number format. Mixing floating point and currencies will generally end badly because binary floating point is unable to represent simple decimal values (like 0.1) without losing accuracy.

With regards NSNumberFormatter, if you want to control how many fractional digits it shows you can do that using the

minimumFractionDigits

and

maximumFractionDigits

properties. For example:

import Foundation

let nf = NSNumberFormatter()
nf.numberStyle = .DecimalStyle
nf.minimumFractionDigits = 3
nf.maximumFractionDigits = 3
print(nf.stringFromNumber(0.123)!)  // -> “0.123”

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Rounding of floats to 2 decimals

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