A memo on regular expressions to check time format in Ruby.

When using it as a validator in Rails, it looks like this:

# Check if time format is correct
def validate_format_for_time
  return if time.blank?

  unless time =~ /^([0-1][0-9]|[2][0-3]):[0-5][0-9]$/
    errors.add(:time, "を正しい形式で入力してください。")
  end
end

That’s all from the Gemba.