jquery selector looping vs using function each

Do these two snippets of code do identical things? If yes, when should one be used over the other? (besides when you need to do something involving i or value)

$("foo").each(function(i,value) {
    $(this).empty();
});

vs.

$("foo").empty();

In general can it be assumed that $("foo").someMethod() means "run somemethod() on each element that matches the selector, except if the name of the method is each? (ie each is a special case)