ruby - Cloning an array with its content

Question

I want to make a copy of an array, to modify the copy in-place, without affecting the original one. This code fails

a = [
  '462664',
  '669722',
  '297288',
  '796928',
  '584497',
  '357431'
]
b = a.clone
b.object_id == a.object_id # => false
a[1][2] = 'X'
a[1] #66X722
b[1] #66X722

The copy should be different than the object. Why does it act like if it were just a reference?

Answer 1

Instead of calling clone on the array itself, you can call it on each of the array's elements using map:

b = a.map(&:clone)

This works in the example stated in the question, because you get a new instance for each element in the array.