Is there a Ruby, or Ruby-ism for not_nil? opposite of nil? method?

user_73673 0
Viewed 69806

I am not experienced in Ruby, so my code feels "ugly" and not idiomatic:

def logged_in?
  !user.nil?
end

I'd rather have something like 

def logged_in?
  user.not_nil?
end

But cannot find such a method that opposites nil?

null ruby-on-rails ruby
7 Answers

May I offer the Ruby-esque ! method on the result from the nil? method.

def logged_in?
  user.nil?.!
end

So esoteric that RubyMine IDE will flag it as an error. ;-)

user_2788420

I arrived at this question looking for an object method, so that I could use the Symbol#to_proc shorthand instead of a block; I find arr.find(&:not_nil?) somewhat more readable than arr.find { |e| !e.nil? }.

The method I found is Object#itself. In my usage, I wanted to find the value in a hash for the key name, where in some cases that key was accidentally capitalized as Name. That one-liner is as follows:

# Extract values for several possible keys 
#   and find the first non-nil one
["Name", "name"].map { |k| my_hash[k] }.find(&:itself)

As noted in other answers, this will fail spectacularly in cases where you are testing a boolean.

user_20635460
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