Popping the first element off an array in Lua

I have an array x in Lua. I would like to set head = x[1] and rest = the rest of the array, so that rest[1] = x[2], rest[2] = x[3], etc.

How can I do this?

(note: I don't care if the original array gets mutated. In Javascript I would do head = x.shift() and x would contain the remaining elements.)