Can an "if (a == b || c == b)" statement be done shorter in Ruby

Question

I have a piece of code in Ruby which goes as follows:

def check
  if a == b || c == b
  # execute some code
  # b = the same variable
  end
end

can this be written like

def check
  if a || c == b
  # this doesn't do the trick
  end
  if (a || c) == b
  # this also doesn't do the magic as I thought it would
  end
end

Or in a manner where I don't need to type b twice. This is out of laziness and I would like to know.

Answer 1

if [a, c].include? b
  # code
end

This is, however, significantly slower than the code you want to avoid -- at least as long as a, b and c are basic data. My measurements showed a factor of 3. This is probably due to the additional Array object creation. So you might have to weigh DRY against performance here. Normally it should not matter, though, because both variants do not take long.