Skip over iteration in Enumerable#collect

Question

(1..4).collect do |x|
  next if x == 3
  x + 1
end # => [2, 3, nil, 5]
    # desired => [2, 3, 5]

If the condition for next is m

Answer 1

You could pull the decision-making into a helper method, and use it via Enumerable#reduce:

def potentially_keep(list, i)
  if i === 3
    list
  else
    list.push i
  end
end
# => :potentially_keep

(1..4).reduce([]) { |memo, i| potentially_keep(memo, i) }
# => [1, 2, 4]