WordPress: save `get_template_part()` to variable

Question

In short, all I need is to make my WordPress do this

$var = get_template_part( \'loop\', \'index\' ); 

but, get_template_part()

Answer 1

what about?

$file = file_get_contents(STYLESHEETPATH . '/template-part.php'); 
return $file;

i'm sure there is a better way, but that seems to work for me.