echo php包含php echo代码的变量

I have a PHP file that echoes a variable:

<?=echo $myVariable;?>

$myVariable is data that I pull from a MySQL variable and it may include code like php echo itself in it:

<div dir="rtl">
    Hello $data['assigned_vars']['first_name'];<br />
    your email <?=$data['assigned_vars']['email'];?><br />
    your password <?=$data['assigned_vars']['user_password'];?>    
</div>

I'm using ob buffering to store the entire string and then return. How can I execute the PHP code inside the PHP string?

You can use eval function,but it makes big security problem for you.

echo eval($string);

but security exception can occurred here,for example following code.

$string = "base64_decode(bXlzcV9xdWVyeSgnREVMRVRFICogRlJPTSBVU0VSJyk7)";
//mysql_query('DELETE * FROM USER'); 
echo eval($string);

and it empty your USER table.

i think that i found my solution. i can just file_put_contents to create temporary html file, then simply include it and then delete the file