Question

my solution is like

if (not (defined?(@results).nil?))
  @results += "run"
else
  @results = "run"
end

but I believe that there is something simpler …

Answer 1

I would probably do it like this:

@results = @results.to_s + "run"

This works because NilClass defines a #to_s method that returns a zero-length String, and because instance variables are automatically initialized to nil.