Question

Is there a quick Ruby or Rails method to delete an element from an Array based on a condition provided in a block and then return that element?

Let’s say, given:

e1.good? # false
e2.good? # true
e3.good? # true
a = [e1, e2, e3]

Is there a method delete_and_return_if doing this:

a.delete_and_return_if { |e| e.good? }      # delete e2 from a and returns e2
[e1].delete_and_return_if { |e| e.good? }   # returns nil

Or at least is there a clean way to do this?

Answer 1

If you do not have duplicates or that you want to delete all same elements, you can do

a.delete(a.detect(&:good?))

• a.detect(&:good?) will return the first good? object or nil if
  there is none.
• a.delete(elem) will delete and return your element.

Or if you have duplicates and only want to delete the first one:

a.delete(a.index(a.detect(&:good?)))