Custom map on `Array`

I have the following problem:

Given an Array, apply a certain method x to each Array element (yielding a new Array), with the restriction that array elements which are nil, should be mapped to some default value. Method and default element are parameters. Example:

Array: ['abc',nil,'defg']

Method: :size

Default element: -1

Expected result: [3, -1, 4]

I implemented this by adding a method map_with to the Array class:

class Array
  def map_with(accessor, default_value=nil)
    map {|e| e.nil? ? default_value : e.send(accessor) }
  end
end

['abc',nil,'defg'].map_with(:size, -1)

I'm looking for an improvement of my current solution. Can the solution be improved in the following sense?

• Provide the same result with simpler code

• Make the function more flexible (more generally useful) by not adding too much code

My implementation is very similar to yours, with only a few small tweaks:

module Enumerable
  def map_with(accessor, default_value: nil)
    map { |e| e.respond_to?(accessor) ? e.send(accessor) : default_value }
  end
end

• Use Enumerable, not Array, so that the method can be applied to other objects such as instances of Hash, Set, etc.

• Use respond_to? rather than a type-check against nil, for better duck-typing robustness.

• Use a named parameter, for improved code clarity.

StackExchange Code Review Q#132110, answer score: 3