PHP可变变量经典示例

最近在使用dede织梦开发一个大型门户网站项目，其中使用到了PHP可变变量，在网上找了一个经典示例，保存下来以备不时之需

<?php
//PHP可变变量经典示例
class foo {
    var $bar = 'I am bar.';
    var $arr = array('I am A.', 'I am B.', 'I am C.');
    var $r   = 'I am r.';
}


$foo = new foo();
$bar = 'bar';
$baz = array('foo', 'bar', 'baz', 'quux');
echo $foo->$bar . "\n";
echo $foo->${$bar} . "\n";
echo $foo->$baz[1] . "\n";


$start = 'b';
$end   = 'ar';
echo $foo->{$start . $end} . "\n";


$arr = 'arr';
echo $arr[0] . ". \n";
echo $foo->$arr[1] . "\n";
echo $foo->{$arr}[1] . "\n";
//以上代码输出为：I am bar. I am bar. I am bar. I am bar. a. I am r. I am B.
?>