Simplify multiple nil checking in Rails

Question

How should I write:

if @parent.child.grand_child.attribute.present?
  do_something

without cumbersome nil checkings to avoid exception:

Answer 1

All these answers are old, so I thought I should share more modern options.

If you are getting an association that might not exist:

@parent&.child&.grand_child&.attribute

if you are reaching into a hash for a key that might not exist:

hash = {
 parent_key: {
   some_other_key: 'a value of some sort'
 },
 different_parent_key: {
   child_key: {
     grand_child: {
       attribute: 'thing'
     }
   }
 }
}
hash.dig(:parent_key, :child_key, :grandchild_key)

Either of these will gracefully return nil if child, grandchild, or attribute don't exist