Swift, converting a number to string, number gets rounded down - ios

Question

I'm having a bit of issue with my code...right now, I am passing a string containing a bunch of numbers, to get converted to a number, comma separators added, then converted back to a string for output. When I add a decimal to my string and pass it in, a number like 996.3658 get truncated to 996.366...
"currentNumber" is my input value, "textOutputToScreen" is my output...
func formatNumber() {
let charset = CharacterSet(charactersIn: ".")
if let _ = currentNumber.rangeOfCharacter(from: charset) {
if let number = Float(currentNumber) {
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
guard let formattedNumber = numberFormatter.string(from: NSNumber(value: number)) else { return }
textOutputToScreen = String(formattedNumber)
}
}
else {
if let number = Int(currentNumber) {
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
guard let formattedNumber = numberFormatter.string(from: NSNumber(value: number)) else { return }
textOutputToScreen = String(formattedNumber)
}
}
}
Thank you in advance for your help!

Answer 1

The issue there is that you have to set your NumberFormatter minimumFractionDigits to 4. Btw there is no need to initialize a NSNumber object. You can use Formatters string(for: Any) method and pass your Float. Btw I would use a Double (64-bit) instead of a Float (32-bit) and there is no need to initialize a new string g from your formattedNumber object. It is already a String.
Another thing is that you don't need to know the location of the period you can simply use contains instead of rangeOfCharacter method. Your code should look something like this:
extension Formatter {
static let number: NumberFormatter = {
let formatter = NumberFormatter()
formatter.numberStyle = .decimal
return formatter
}()
}
func formatNumber(from string: String) -> String? {
if string.contains(".") {
guard let value = Double(string) else { return nil }
Formatter.number.minimumFractionDigits = 4
return Formatter.number.string(for: value)
} else {
guard let value = Int(string) else { return nil }
Formatter.number.minimumFractionDigits = 0
return Formatter.number.string(for: value)
}
}
let label = UILabel()
let currentNumber = "996.3658"
label.text = formatNumber(from: currentNumber) // "996.3658\n"
If you would like to assign the result to your var instead of a label
if let formatted = formatNumber(from: currentNumber) {
textOutputToScreen = formatted
}