how to get if a string is present in a setence in php code example

Example 1: if part of stringp ph

$a = 'How are you?';

if (strpos($a, 'are') !== false) {
    echo 'true';
}

Example 2: php check if string contains

// returns true if $needle is a substring of $haystack
function contains($haystack, $needle){
    return strpos($haystack, $needle) !== false;
}