iOS Swift. How to convert a string with comma to a string with decimal

When you need to convert string to double or float value there might be a problem with separator inside string (comma or dot). For converting your string to number you can use NumberFormatter. You just need to specify the decimal separator:

import Foundation
import UIKit

extension String {
    
    var convertCommaToDecimal: Double {
        let numberFormatter = NumberFormatter()
        numberFormatter.decimalSeparator = "."
        if let result = numberFormatter.number(from: self) {
            return result.doubleValue
        } else {
            numberFormatter.decimalSeparator = ","
            if let result = numberFormatter.number(from: self) {
                return result.doubleValue
            }
        }
        return 0
    }
    
}

And the result

"3.57".convertCommaToDecimal // 3.57
"3,57".convertCommaToDecimal // 3.57