合并变量PHP

Question

我很困惑......

像例子:

$Q1 = "hello";
$Q2 = "world";
$Q3 = "StackOverflow";

$i = 1;

while($i < 3) {
  $a = "$Q".$i; //I think this is wrong.    
  echo $a; // i tried ${$a} doesn't work =/

  $i++;
}

然后输出格式:

$Q1
$Q2
$Q3

但是没有这样的输出:hello world StackOverflow

我想$Q + $i成为$Q1回答的是:"你好"......

Answer 1

$varName = 'Q'.$i;
$a .= $$varName; 

要不就

echo $$varName . "<br>\n";