Convert list (array) to associative array in PHP


I want to convert PHP list (array), i.e.

array("start", "end", "coords")

into associative array with truthy values (just to be able to test the presence/absence of key quickly), i.e. to something like this:

    "start" => 1,
    "end" => 1,
    "coords" => 1

Is there any more elegant way to do it than this?

array_fill_keys($ar, 1)

There is probably no more elegant solution than array_fill_keys($ar, 1).