带有分组分隔符的字符串中的 Numberformatter 数字

Question

I have a NumberFormatter which has a currency number style. I can successfully format my number to string. However, when I try to get number from string, It returns null. The problem occurs when string has grouping separator.

My formatter:

let groupingSeparator = "."
let decimalSeparator = ","
let formatter = NumberFormatter()
formatter.maximumIntegerDigits = 6
formatter.maximumFractionDigits = 2
formatter.minimumFractionDigits = 0
formatter.numberStyle = .currency
formatter.groupingSize = 3
formatter.groupingSeparator = groupingSeparator
formatter.currencyGroupingSeparator = groupingSeparator
formatter.usesGroupingSeparator = true
formatter.decimalSeparator = decimalSeparator
formatter.currencyDecimalSeparator = decimalSeparator
formatter.currencySymbol = viewModel?.currency?.symbol ?? ""

How I try to get number from string:

if let number = amountFormatter.number(from: currentInput) {
        text = amountFormatter.string(from: number)
}

Working Texts:

$1459
$2345,23

Not working Texts:

$1.459
$2.333,49

Answer 1

I suspect that your let constant groupingSeparator is empty. When I run the following code:

let groupingSeparator = "."

let formatter = NumberFormatter()
formatter.maximumIntegerDigits = 6
formatter.maximumFractionDigits = 2
formatter.minimumFractionDigits = 0
formatter.numberStyle = .currency
formatter.groupingSize = 3
formatter.groupingSeparator = groupingSeparator
formatter.currencyGroupingSeparator = groupingSeparator
formatter.usesGroupingSeparator = true
formatter.decimalSeparator = decimalSeparator
formatter.currencyDecimalSeparator = decimalSeparator



let strings = ["$1459",
               "$2345,23",
               "$1.459",
               "$2.333,49"
]

strings.forEach { value in
    let string = formatter.number(from: value)?.description ?? "nil"
    print("Value for \"\(value)\" = \(string)")
}

I get the output

Value for "$1459" = 1459
Value for "$2345,23" = 2345.23
Value for "$1.459" = 1459
Value for "$2.333,49" = 2333.49

Exactly as expected.

(Note that I'm in the US, so the default output for NSNumber.description uses a "." decimal separator.)