How to append to a nil object in Rails iterating through a loop?

Question

  @preComments = Comment.where(:resource_hash => resource_hash).sort(:created_at.desc).all
  @preComments.each do |comment|
    u = ::User.find_by_id comment.user_id
    p u
    @comments << @preComments
    p "HERE!!!!!"
  end

That's my code, but @comments isn't defined so I get an error:

You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil.<<

If I create an array first, then my view can't read it. So how do I do this?

I answered below, but if you give a better description of what you're trying to achieve with @preComments vs @comments, there might be a better way. — Dylan Markow
– Dylan Markow, Commented Jan 17, 2012 at 19:14
Could you please give more detail why your view can't read @comments if you create an array first ? — Thong Kuah
– Thong Kuah, Commented Jan 17, 2012 at 20:14

MrTheWalrus · Accepted Answer · 2012-01-17 19:14:30Z

1

The problem is that the first time you iterate, you want to create the @comments array (containing that item), but all subsequent times you want to push that item onto the existing array. There's probably a more elegant way to do this, but I generally just do this:

@comments ? @comments = [comment] : @comments << comment

answered Jan 17, 2012 at 19:14

MrTheWalrus

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Dylan Markow · Accepted Answer · 2012-01-17 19:14:01Z

0

Create the array before the loop using @comments = [], then in the loop make sure you're using @comments << comment, not @comments << @preComments.

answered Jan 17, 2012 at 19:14

Dylan Markow

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vicosanz · Accepted Answer · 2012-01-17 20:06:20Z

0

I think you must initialize array

@preComments = Comment.where(:resource_hash => resource_hash).sort(:created_at.desc).all
@comments = []
@preComments.each do |comment|
  u = ::User.find_by_id comment.user_id
  p u
  @comments << comment
  p "HERE!!!!!"
end

or when loop is finished then pass values of @preComments to @comments

@preComments = Comment.where(:resource_hash => resource_hash).sort(:created_at.desc).all
@preComments.each do |comment|
  u = ::User.find_by_id comment.user_id
  p u
  p "HERE!!!!!"
end
@comments = @preComments

answered Jan 17, 2012 at 20:06

vicosanz

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