I would like to sort an array of objects by a variable of an object variable.
I have an array of objects (obj_array).
One of the variables of (obj_a) is an object (obj_b).
I want to sort by a variable of (obj_b).
So I want to sort an
$obj_array = array (
$butter = new obj_a,
$flour = new obj_a,
$water = new obj_a
where obj_a has a variable object called obj_b and obj_b has variable called volume