1 // MARK: - UITextFieldDelegate
 2     func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
 3         guard string == "." || string == "0" else {
 4             //限制输入个数{0,2},0-2
 5             /*
 6              let newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)
 7              
 8              //纯整数，限制只有6位{0,6}。如果是小数，就小数点前6后8位{0,8}
 9              //let expression = "^[0-9]{0,6}?$*((\\.|,)[0-9]{0,8})?$" 
10              let expression = "^[0-9]*((\\.|,)[0-9]{0,2})?$"
11              let regex = try! NSRegularExpression(pattern: expression, options: NSRegularExpression.Options.allowCommentsAndWhitespace)
12              let numberOfMatches = regex.numberOfMatches(in: newString, options:.reportProgress, range: NSMakeRange(0, (newString as NSString).length))
13              return numberOfMatches != 0
14              */
15             
16             //无限制
17             return true
18         }
19         
20         guard let text = textField.text else { return true }
21         if text.count == 0 {
22             textField.text = "0."
23             return false
24         }
25         
26         if text.range(of: ".") != nil && string == "." {
27             return false
28         }
29         
30         return true
31     }