Putting a variable between double quotes before echoing?

Question

Now and then I'll see code like

$str = strip_tags($str)
echo "$str";

Does that do anything at all? Why put the variable in quotes instead of echoing it directly?

Answer 1

It's just a terrifically common misunderstanding of new (PHP) programmers. It happens to work exactly the same as not quoting the variable at all, but is entirely superfluous. I'd love to know as well why people think this is necessary; but one can see it surprisingly often.