What does !! mean in ruby?
ruby
Solution
Not not.
It's used to convert a value to a boolean:
!!nil #=> false
!!"abc" #=> true
!!false #=> false
It's usually not necessary to use though since the only false values to Ruby are `nil` and `false`, so it's usually best to let that convention stand.
Think of it as
!(!some_val)
One thing that is it used for legitimately is preventing a huge chunk of data from being returned. For example you probably don't want to return 3MB of image data in your `has_image?` method, or you may not want to return your entire user object in the `logged_in?` method. Using `!!` converts these objects to a simple `true`/`false`.
Problem
Just wondering what `!!` is in Ruby.