[PHP] is_array() vs. identical (===)

function calc($t0, $t1)
{
    $v0 = array_sum(explode(' ', $t0));
    $v1 = array_sum(explode(' ', $t1));
    $sub = $v1 - $v0;
    echo "$v1 - $v0 = $sub\n";
    return $sub;
}

$a = array();
$b = array(1);
$c = '';

$t0 = microtime();
for ($i = 0; $i < 1E6; $i++) {
    is_array($a);
    is_array($b);
    is_array($c);
}
$t1 = microtime();
$method1 = calc($t0, $t1);     // output: 1420785145.2006 - 1420785142.9861 = 2.2144329547882

$t0 = microtime();
for ($i = 0; $i < 1E6; $i++) {
    $a === (array) $a;
    $b === (array) $b;
    $c === (array) $c;
}
$t1 = microtime();
$method2 = calc($t0, $t1);     // output: 1420785142.986 - 1420785142.2001 = 0.78591012954712

echo ($method1 - $method2) / $method1; // output: 0.64509644428486

從測試中可以知道 is_array() 比較慢。

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