Ruby array delete if and get deleted object

Question

So I have this situation where I need to delete something from an array conditionally, meaning that I want to go through the items in the array and do a test and delete the one that passes the test, and then I want to get that deleted item back. If I exclude the conditional aspect of this then Array#delete does what I want basically--returns the deleted item, but can't delete conditionally. On the other hand delete_if removes the item conditionally, but returns the remaining items back in an array.

For the purposes of this question assume the following class:

class Foo
  def test?
    #returns true or false
  end
end

I can easily reproduce this behavior by doing:

index = my_array.index {|a| a.test?}
item_to_delete = my_array[index]
my_array.delete item_to_delete

But I was hoping to find something like:

deleted_item = my_array.delete_if_and_return_deleted {|a| a.test?}

I'm not thrilled about having to go through the array multiple times to get this done :/ first to find the target's index, second to get the target and third to remove the target. Ick.

Any thoughts or suggestions?

Answer 1

What you want is the partition method:

deleted_items, kept_items = my_array.partition {|a| a.test?}