PHPの配列とオブジェクトのコピー

arr_copy.php

<?php
$a = array( "n" => 1 );
$_a = $a; // コピー
$_a["n"] = 2;
echo $a['n'], "\n";  // 1
echo $_a['n'], "\n"; // 2

obj_copy_ng.php

<?php
$o = new stdClass;
$o->n = 1;
$_o = $o; // コピーしたつもり
$_o->n = 2;
echo $o->n, "\n";  // 2
echo $_o->n, "\n"; // 2

obj_copy_ok.php

<?php
$o = new stdClass;
$o->n = 1;
$_o = clone $o; // clone でコピー
$_o->n = 2;
echo $o->n, "\n";  // 1
echo $_o->n, "\n"; // 2