     }
     
     func toDate(format: String = "yyyy-MM-dd") -> NSDate? {
-        let dateFormatter = NSDateFormatter()
-        dateFormatter.dateFormat = format
-        return dateFormatter.dateFromString(self)
+        return dateFormatter(format).dateFromString(self)
     }
     
     func toDateTime(format: String = "yyyy-MM-dd HH:mm:ss") -> NSDate? {

    }
    
    func isNumeric() -> Bool {
        if let _ = NSNumberFormatter().numberFromString(self) {
            return true
        }
        return false

    }
    
    func toFloat() -> Float? {
        if let number = defaultNumberFormatter().numberFromString(self) {
            return number.floatValue
        }
        return nil
    }
    
    func toInt() -> Int? {
        if let number = defaultNumberFormatter().numberFromString(self) {
            return number.integerValue
        }
        return nil
    }
    
    func toDouble(locale: NSLocale = NSLocale.systemLocale()) -> Double? {
        let nf = localeNumberFormatter(locale)

        if let number = nf.numberFromString(self) {
            return number.doubleValue
        }
