What's the way to check if all the elements in

Question

This question already has an answer here:

• How do I check if there's a nil set or not in an array? 5 answers

I would like to know if there's anything except nil values in an array.

arr = [nil, nil, nil, nil] # => true
arr = [nil, 45, nil, nil] # => false

There could be any values of any types (not only 45).

Answer 1

Use the Enumerable#all? method:

p arr.all? { |x| x.nil? }

Or

p arr.all?(&:nil?)

As @Stefan suggested,

 p arr.all?(NilClass) #works only for Ruby 2.5

Answer 2

you could do arr.compact.empty?, compact gets rid of all the nil for you

you could read here at ruby guides to find about all the methods on Array class

Answer 3

You can also use #any? method for array

[nil, 45].any?
=> true
[nil, nil].any?
=> false

From the documentation:

If the block is not given, Ruby adds an implicit block of {|obj| obj} (that is any? will return true if at least one of the collection members is not false or nil.

Note: This won't work if false boolean values are present.

[nil, false].any?
=> false # It should return `true`

Other options would be:

arr = [nil, nil, 45]
arr.count(nil) == arr.length
=> false

(arr - [nil]).empty?
=> false