What are the potential pitfalls when comparing the return value of strpos in PHP to TRUE or FALSE?

When comparing the return value of strpos in PHP to TRUE or FALSE, the potential pitfall is that strpos can return 0 if the needle is found at the beginning of the haystack, which can be interpreted as FALSE in a loose comparison. To solve this issue, you should use strict comparison (===) to check if the return value is exactly equal to FALSE. 

$haystack = "Hello, world!";
$needle = "Hello";

if (strpos($haystack, $needle) !== false) {
    echo "Needle found in haystack!";
} else {
    echo "Needle not found in haystack!";
}

Keywords

strpos return value comparison boolean type coercion

Related Questions