在 PHP 中,函數(shù)參數(shù)可以通過值傳遞或引用傳遞。它們之間的主要區(qū)別在于數(shù)據(jù)如何傳遞給函數(shù)以及函數(shù)內(nèi)部如何操作這些數(shù)據(jù)。以下是值傳遞和引用傳遞之間的區(qū)別:
值傳遞(Pass by Value):
function add_num($num1, $num2) {
$num1 = $num1 + $num2;
return $num1;
}
$a = 10;
$b = 20;
$c = add_num($a, $b);
echo $a . ", " . $b . ", " . $c; // 輸出 10, 20, 30
引用傳遞(Pass by Reference):
function add_num_ref(&$num1, &$num2) {
$num1 = $num1 + $num2;
return $num1;
}
$a = 10;
$b = 20;
$c = add_num_ref($a, $b);
echo $a . ", " . $b . ", " . $c; // 輸出 30, 20, 30
總結(jié):