Use [].replace to make a copy of an array

Question

I have a class where I was using the Array#shift instance method on an instance variable. I thought I made a \"copy\" of my instance variable but in fact I hadn

Answer 1

The preferred method is dup

• use array.dup whenever you need to copy an array
• use array.map(&:dup) whenever you need to copy a 2D array

Don't use the marshalling trick unless you really want to deep copy an entire object graph. Usually you want to copy the arrays only but not the contained elements.