PHP - Error parsing a string with code

Answer 1

My guess is that PHP is catching on the re-opening of the php tag <?php, try splitting just that:

$str2 = "<?" . "php print( \$myVar$myVar2 );  ?>";

Or use single quotes and concatenation:

$str2 = '<?php print( $myVar' . $myVar2 . ' );  ?>';

Answer 2

Cryo is on the right track, though I think the actual issue is that PHP evaluates variables within double-quoted strings. However, the slash should prevent the variable from being evaluated. So:

$a = "somestring"
$b = "\$a" // -> \$a
$c = '\$a' // -> \$a

I think your string is getting evaluated in an odd way such that the \ + $myVar is evaluated in a strange way.