Consider an array having only one value nil
array = [nil]
Is there any better way to check whether an array is nil or not, like array.nil??
This works:
array == [nil]
But what if there are multiple nil values in the array?
array = [nil, nil, nil]
Below is the requirement:
array = [1, 2] if array.nil?
array.nil? should also give 'true' when array = [nil, nil, nil]
You can use Array#any? to check if the array contains at least one value that is not false or nil:
array = [1,2] unless array.any?
If array is allowed to contain false and you are interested only in nil then Array#any? needs a block:
array = [1,2] unless array.any?{|i| !i.nil?}
Update
As @mu-is-too-short suggests, a better version is:
array = [1,2] if array.all?(&:nil?)
It does exactly what you need: Enumerable#all? returns true if the block returns a true-ish value for all elements of the array.
array = [1,2] if array.all?(&:nil?) to avoid all the negations.
all? was the method I was looking for but it is not listed in the documentation of Array and I forgot to check in the documentation of Enumerable. Thank you.One option is to uniquify your array and then do what you were already doing:
array.uniq == [nil]
So if array is any amount of nils it will be true. On the other hand:
array.nil?
Checks whether array itself is nil, which is not the same as an array containing nil elements.
array.uniq.first.nil?
[nil,nil,2].uniq -> [nil,2]) your test will be invalid.[2, nil,nil,2]
array is empty this returns false. That may be OK, but maybe not. The OP has not stated whether array could be empty and, if so, what is to be returned when it is empty. Rhunhl?array which is not empty, it can contain nil or any value. Because I am passing env var in array, e.g. [ENV['var']]. So it will be never empty.One of possible ways is to remove nil values with .compact and check if the result is empty? .
array = [1, 2] if array.compact.empty?
arrayarenilor if all elements ofarrayarenil?array.all?(&:nil?). Says exactly what you're trying to do.nilvalues come from? What do they indicate?array.compact.empty?, butall?(&:nil?)is both idiomatic and potentially faster since it would terminate on the first nonnilvalue.