正确:
<?php $arr = array( "a" => array( "a" => "1", ), ); foreach ($arr as $a => &$trdata) { $trdata['b'] = $trdata['a']; } var_dump($arr); ?>
错误:
<?php $arr = array( "a" => array( "a" => "1", ), ); foreach ($arr as $a => $trdata) { $trdata['b'] = $trdata['a']; } var_dump($arr); ?>