title: Find the first character from the word and replace it
body: <p>I want to find the first character of the word from the sentence and I want to replace it with some other character. </p>
  
  <p><strong>eg    '9322731525 , 9820231525, 23856141 , 9321154466'</strong> </p>
  
  <p>find character 2 at 1st position and replace it so the output would look like </p>
  
  <p><strong>eg    '9322731525 , 9820231525, <em>93856141</em> , 9321154466'</strong>. </p>
  
  <p>I tried using <code>substr</code> but it didn't work.</p>