Multiple ORs in if-else

Question

How do I refactor this in Rails?

if formatted_address.blank? || country.blank? || lat.blank? || lng.blank?
  ...
end

If I have 10 attributes to check if blank, I don't wanna retype .blank? 10 times.

Thanks.

If I have 10 attributes to check if blank, I don't wanna retype .blank? 10 times.
From the maintainability standpoint, multiple ORs or || are the same and you should opt to list them all. Just come up with the proper formatting - in this case if your underlying objects changes in structure, you can quickly update the condition. At the same time you may want to have all these conditions compiled into an aggregate field within the parent entity (the one that has "formatted_address" properties) but I dont see a big point in it based on the context.

Flambino · Accepted Answer · 2012-11-07 01:29:44Z

up vote 3 down vote accepted

You could do this. You still have a list of attributes, in case you need to change them later

if [formatted_address, country, lat, lng].any? { |field| field.blank? }
  # ...
end

Edit: By the way, the above can be shortened to:

if [formatted_address, country, lat, lng].any?(&:blank?)
  # ...
end

edited Nov 7 '12 at 1:29

answered Oct 10 '12 at 18:21

Flambino
3,087110

Prathamesh Sonpatki · Answer 2 · 2012-10-10 15:05:26Z

You can use or instead of ||. In Ruby or and and are used for control flow. So

(expr1) or (expr2)

If expr1 is false then expr2 will be evaluated. This is similar to failsafe condition. In your case, all if conditions can be combined using or

formatted_address.blank? or country.blank? or lat.blank? or lng.blank?

With this, all conditions will be checked but if any one of them is true, we want to execute some code. That can be achieved by using and

formatted_address.blank? or country.blank? or lat.blank? or lng.blank? and do_something

If your do_something is small enough this approach is useful.

More information about or and and in Ruby is here

2 Answers