iTextSharp.text.pdf.BarcodeInter25.KeepNumbers C# (CSharp) Метод

        public static string KeepNumbers(string text) {
            StringBuilder sb = new StringBuilder();
            for (int k = 0; k < text.Length; ++k) {
                char c = text[k];
                if (c >= '0' && c <= '9')
                    sb.Append(c);
            }
            return sb.ToString();
        }