Remove link if contains specific string

Question

I have this PHP code where a specific word is converted to link before sending in email.

$message = str_replace(
           'hello',
           '<a id="get-ahead-link" style="color: #ffa503;" href="https://somelink.com"> hello </a>',
           $message,
           $count);

The code above is completely working but I got an issue when a link with the word 'hello' is already included.

Example:

hello world. Please visit my site: http://helloworld.com.

This becomes:

hello world. Please visit my site: http://helloworld.com.

But what I need:

hello world. Please visit my site: http://helloworld.com.

Is this possible? What am I missing with my work?

Answer 1

You could use preg_replace (replacement using regular expressions) and surround your string with (?<=^|\s) ("is either at the beginning of the string or preceded by a space character") and \b (word boundaries):

$message = preg_replace(
  '/(?<=^|\s)hello\b/', 
  '<a id="get-ahead-link" style="color: #ffa503;" href="https://somelink.com">hello</a>', 
  $message, 
  -1, 
  $count
);

Demo: https://3v4l.org/SknUT

Note: I left the additional parameters to retrieve $count.

Other (unrelated) note: such inline HTML styles should be avoided in most cases.