How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators differ?

Question

What is the difference between == and === in PHP?

What would be some useful examples?

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Additionally, how are these operators us

Answer 1

You would use === to test whether a function or variable is false rather than just equating to false (zero or an empty string).

$needle = 'a';
$haystack = 'abc';
$pos = strpos($haystack, $needle);
if ($pos === false) {
    echo $needle . ' was not found in ' . $haystack;
} else {
    echo $needle . ' was found in ' . $haystack . ' at location ' . $pos;
}

In this case strpos would return 0 which would equate to false in the test

if ($pos == false)

or

if (!$pos)

which is not what you want here.