Basic PHP Programming Question:

What Is the Best Way to Test the strpos() Return Value in PHP?

PHP Interview Question
PHP Interview Question

Answer:

Because strpos() could two types of values, Integer and Boolean, you need to be careful about testing the return value. The best way is to use the "Identical(===)" operator. Do not use the "Equal(==)" operator, because it does not differentiate "0" and "false". Check out this PHP script on how to use strpos():

<?php
$haystack = "needle234953413434516504381640386488129";
$pos = strpos($haystack, "needle");
if ($pos==false) {
print("Not found based (==) test ");
} else {
print("Found based (==) test ");
}
if ($pos===false) {
print("Not found based (===) test ");
} else {
print("Found based (===) test ");
}
?>

This script will print:

Not found based (==) test
Found based (===) test

Of course, (===) test is correct.


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