如何使用php中的字符串内的条件

问题描述：

我想知道是否有办法使用这样的东西：

I want to know if there is a way to use something like this:

$t1=1;
$t2=2;
$t3="$t1>$t2";

if($t3)
   echo "Greater";
else
   echo "Smaller";

这将评估为真，因为$ t3是一个字符串，但这是错误的！

This will evaluate to true as $t3 is a string, but that's wrong!!!

那么有没有办法在字符串中包含if条件。

So is there a way to include the if condition inside string.

我听说我们可以使用eval：
PHP - 如果字符串内的条件

I heard that we can use eval for this: PHP - if condition inside string

但是这怎么可能???

But how is this possible???

答

看起来它应该可行，给定PHP 评估页面。

This looks like it should work, given the PHP eval page.

$t1=1;
$t2=2;
$t3="return $t1>$t2;";

if(eval($t3))
   echo "Greater";
else
   echo "Smaller";