How to assign to a variable in smarty php?

Question

PHP

A product variant is assigned and passed to the order, how to make a condition so that if the variant is empty then variant='1' ?

if($('.variants').find('select[name=variant]').size()>0) variant = $('.variants').find('select').val();

Answer 1

if($('.variants').find('select[name=variant]').size()<0) variant='1';
just changing <> doesn't help