CODEWITHSUNDEEP
ruby
Kirill Zhuravlov
Kirill Zhuravlov

Reputation: 464

Ruby: How to check that all elements in array are negative integers

I have the arrays a = [-1,-2,-3,-4] and b = [-1,-2,-3,4]

How can I make sure that a contains only negative integers? I can check that some of elements are negative a.select(&:negative?) == true and b.select(&:negative?) == true

But I need to know that b.select(&:negative?).only == true

Upvotes: 4

Views: 5901

Answers (2)

Cary Swoveland
Cary Swoveland

Reputation: 110685

You could simply consider the largest value:

arr = [-1,-2,-3,-4]
arr.empty? ? false : arr.max < 0
  #=> true

if the array contains only integers. If the array may contain elements that are not integers, one must first confirm that only integers are present.

arr = [-1,-2,-3,-4, "cat", { a:1 }]
return false unless arr.all? { |e| e.is_a?(Fixnum) }
  #=> false returned

Upvotes: 6

Andrey Deineko
Andrey Deineko

Reputation: 52357

You can use Enumerable#all? here:

[-1,-2,-3,-4].all?(&:negative?)
#=> true

Btw, I think you are confused with what is happening here:

a.select(&:negative?) == true

This is not checking whether all elements are negative. What it is in fact is comparing resulting array of negative numbers with false:

[-1,-2,-3,-4] == false

Of course, it will always return false, because only false is equal to false.

Upvotes: 16

Related Questions