> For the complete documentation index, see [llms.txt](https://learnphp.gitbook.io/learnphp/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://learnphp.gitbook.io/learnphp/xay-dung-method-is_tel-ricycle-1.4.md).

# Xây dựng method is\_tel Ricycle 1.4

```
private function is_tel($value) {
    if (!empty($value)) {
      return true;
    }

    if (preg_match("/^\d+(-*)\d+(-*)\d+$/", $value)) {
      return true;
    } else {
      return false;
    }
  }
```