Checking for empty elements within my array - Ruby

Question

I have an element in my array that when I print out the value of that specific element I get an empty value.

puts my_listing[2].inspect
[]

When I check to see if that specific element is empty, using empty? it returns true:

puts my_listing[2].empty?
true

But when I cycle through the entire array, checking to see if i is empty, it doesn't find that particular element.

my_listing.each do |i|
    if i.empty?
        puts i
    end
end

i (in this case 2) is never printed to the screen.

Why is that?

Basically, I am trying to get rid of all the elements in the array that are empty (in this case the element at index 2) but I am not sure how to even get at those elements.

What am I missing?

Thanks.

Jessehz · Accepted Answer · 2012-05-10 11:11:29Z

7

You're not seeing anything printed because you forgot to use #inspect You could also just have written:

my_listing.each do |i|
    i.empty? and p i
end

To remove empty elements, you can do the following:

my_array = [[1],[2],[],[4]]

p my_array.reject(&:empty?) # => [[1], [2], [4]]

reject calls #empty? on all the elements and removes the ones which are empty

answered May 10, 2012 at 11:11

Jessehz

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Comments

Muhammad Kashif Ali · Accepted Answer · 2012-05-10 10:55:12Z

0

Oh please iterate like this

       my_listing.each_with_index do |i,index|
          if i.blank?
             puts index.inspect
          end
       end

It give you index of array which will be empty or nil.

answered May 10, 2012 at 10:55

Muhammad Kashif Ali

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5 Comments

marcamillion Over a year ago

the method .blank? doesn't work, but .empty? does. Thanks.

marcamillion Over a year ago

FYI: this is the error I get when I do .blank? - NoMethodError: undefined method 'blank?' for []:Nokogiri::XML::NodeSet. I am using Nokogiri and am storing a node in an array.

marcamillion Over a year ago

How do I pop an element that is empty? I tried doing i.pop in the each, but that didn't work. Neither did index.pop. Thoughts?

marcamillion Over a year ago

Never mind, I tried reject! like @jessehz suggested and it worked beautifully.

Colin Bradley Over a year ago

In case you were wondering - .blank? is a Rails extension method which checks for .nil? and .empty? (at least as far as I remember). If you're not in Rails then it would explain why it doesn't work!

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