Understanding the “||” OR operator in If conditionals in Ruby

Question

Just briefly, why are the following three lines not identical in their impact?

if @controller.controller_name == \"projects\" || @controller.controller_name          


        

Answer 1

The logical or operator || works on boolean expressions, so using it on strings doesn't do what you want.

There are several ways to achieve what you want that are less verbose and more readable.

Using Array#include? and a simple if-statement:

if ["projects", "parts"].include? @controller.controller_name
  do_something
else
  do_something_else
end

Using a case-statement:

case @controller.controller_name
when "projects", "parts" then
  do_something
else
  do_something_else
end