数组如何配合可变变量打印或做判断

<?php
	error_reporting(E_ALL || ~E_NOTICE);//设置忽略警告
	echo "3.自动类型转换--将其他值抓换成布尔型"."<br />";
	$varNameArray = array("intZero","floatZero","stringNull","stringZero","arrayNull","varNull");
	$intZero = 1234;
	$floatZero = 1;
	$stringNull = "";
	$stringZero = "0";
	$arrayNull = array();
	$varNull = NULL;
	for ($i=0; $i < count($varNameArray); $i++) { 
		//$var = $varNameArray[$i];
		if (${$varNameArray[$i]} == false) { //关键点在于 ${$ ,如果直接写成 $$ 则php不会正确的解析数组索引出正确的值并最后输出可变变量.
			echo "var ".$varNameArray[$i]." value is [".${$varNameArray[$i]}."] to boolean result is false";
		}else{
			echo "var ".$varNameArray[$i]." value is [".${$varNameArray[$i]}."] to boolean result is true";
		}
		echo "<br />";
	}
?>