How do I check if a string contains a specific word?

Answer 1

In PHP, the best way to verify if a string contains a certain substring, is to use a simple helper function like this:

function contains($haystack, $needle, $caseSensitive = false) {
    return $caseSensitive ?
            (strpos($haystack, $needle) === FALSE ? FALSE : TRUE):
            (stripos($haystack, $needle) === FALSE ? FALSE : TRUE);
}

Explanation:

• strpos finds the position of the first occurrence of a case-sensitive substring in a string.
• stripos finds the position of the first occurrence of a case-insensitive substring in a string.
• myFunction($haystack, $needle) === FALSE ? FALSE : TRUE ensures that myFunction always returns a boolean and fixes unexpected behavior when the index of the substring is 0.
• $caseSensitive ? A : B selects either strpos or stripos to do the work, depending on the value of $caseSensitive.

Output:

var_dump(contains('bare','are'));            // Outputs: bool(true)
var_dump(contains('stare', 'are'));          // Outputs: bool(true)
var_dump(contains('stare', 'Are'));          // Outputs: bool(true)
var_dump(contains('stare', 'Are', true));    // Outputs: bool(false)
var_dump(contains('hair', 'are'));           // Outputs: bool(false)
var_dump(contains('aren\'t', 'are'));        // Outputs: bool(true)
var_dump(contains('Aren\'t', 'are'));        // Outputs: bool(true)
var_dump(contains('Aren\'t', 'are', true));  // Outputs: bool(false)
var_dump(contains('aren\'t', 'Are'));        // Outputs: bool(true)
var_dump(contains('aren\'t', 'Are', true));  // Outputs: bool(false)
var_dump(contains('broad', 'are'));          // Outputs: bool(false)
var_dump(contains('border', 'are'));         // Outputs: bool(false)