How can one troubleshoot and resolve the issue of substr_count returning 0 in PHP?

The issue of substr_count returning 0 in PHP may occur due to incorrect parameters being passed to the function. To resolve this, ensure that the string and substring being searched for are correctly specified. Additionally, check for any case sensitivity issues that may be causing the function to return 0.

// Example code snippet to troubleshoot and resolve substr_count returning 0
$string = "Hello, world!";
$substring = "hello"; // Note the case sensitivity issue here

// Use strtolower to make the comparison case-insensitive
$count = substr_count(strtolower($string), strtolower($substring));

echo $count; // Output: 1