How to remove extra characters in phone link when displaying in WordPress (backend)?

Question

PHP

Can you please tell me how to remove extra characters in the link to the phone when displaying in WordPress?
I am displaying the phone number via theme-options.php. The phone number contains spaces and the characters "(" and ")". And in order for the number in the link (href="tel:....") to be correct, these characters must not be there, so you need to cut them out with some function, tell me.

<a href="tel:<?php
  $options = get_option('sample_theme_options');
  echo $options['phonetext']; ?>">

  <?php
  $options = get_option('sample_theme_options');
  echo $options['phonetext']; ?>
</a>

Answer 1

Most reliable using regular expressions, for example using the preg_replace function

Answer 2

Solved the problem this way:

<a href="tel:+<?php
  $options = get_option('sample_theme_options');
  $options = preg_replace('![^0-9]+!', '', $options);
  echo $options['phonetext']; ?>">

  <?php
  $options = get_option('sample_theme_options');
  echo $options['phonetext']; ?>
</a>