Ruby - "can't convert Symbol into Integer" when try to access data in array

Question

Here's a sample of array:

{"C1"=>[
        {:upc=>"51857195821952", :product_id=>"1234", :name=>"name", :price=>" $15 ", :color=>"green", :size=>"L", :description=>"descr"},
        {:upc=>"352353wegs", :product_id=>"456", :name=>"name2", :price=>"$21", :color=>"black", :size=>"S", :description=>"descr"}, # ...
       ],
 #...
}

And here as I am trying to fetch data from that array:

@array.each do |p|
  product = Product.new
  product.sku = p[0]
  product.name = p[1][0][:name] #can't convert Symbol into Integer
  price = p[1].select{ |pr| !pr[:price].nil? and pr[:price] != "0" }.min_by{ |i| i[:price].to_f }[:price]
  product.price = "%.2f" % (price.to_f)
  ...
end

Every time I try to fetch data from the array, I get on the line product.name = the error can't convert Symbol into Integer.

What is wrong in this case? I spent a part of afternoon on this issue, but unfortunately I still cannot figure out it...

Thanky you

MrYoshiji · Accepted Answer · 2013-02-27 21:38:46Z

5

Your @array is actually a hash. It is formated like following:

{ 
  'name1' => [{:upc => "..."},{:upc => "..."}],
  'name2' => [{:upc => "..."},{:upc => "..."}],
  #...
}

Since it is a Hash, you can use 2 arguments in the each (works for map also) method (one for the key, the other for the value):

@array.each do |name, array|
  product = Product.new
  product.sku = name # returns "C1"
  array.each do |data|
    data[:upc]
    data[:name]
    #etc...
  end
end

edited Feb 27, 2013 at 21:38

answered Feb 27, 2013 at 21:26

MrYoshiji

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2 Comments

user984621 Over a year ago

thank you. But how can I access the price element? The current way how I am trying to obtain that generate error private method 'select' called for "\"":String

MrYoshiji Over a year ago

You can access to it using data[:price] but this will return a string like " 15$ ", you have to strip it and gsub the '$' before converting it into a Float

Jason Kim · Accepted Answer · 2013-02-27 21:30:00Z

0

The fundamental problem is that the sample array you showed above is not actually an array. It's a hash with key-value pairs. Therefore, your code like p[0] or p[1][0] doesn't make sense because a hash doesn't have index like array. Hash is not ordered. Hashes values are accessed with a "key" rather than an "index" like array.

Iterating through key-value pairs of a hash is done something like this.

1.9.3p194 :001 > x = {:x => 10, :y => 9, :z => 10}
 => {:x=>10, :y=>9, :z=>10} 
1.9.3p194 :002 > x.each do |key, value|
1.9.3p194 :003 >   puts "#{key} : #{value}"
1.9.3p194 :004?> end 
x : 10
y : 9
z : 10
 => {:x=>10, :y=>9, :z=>10}

answered Feb 27, 2013 at 21:30

Jason Kim

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Comments

Kevin Bedell · Accepted Answer · 2013-02-27 21:33:23Z

It looks like you may be confusing Arrays and Hashes a bit.

Given this:

@array = {"C1"=>[
  {:upc=>"51857195821952", :product_id=>"1234", :name=>"name", :price=>" $15 ", :color=>"green", :size=>"L", :description=>"descr"}, 
  {:upc=>"352353wegs", :product_id=>"456", :name=>"name2", :price=>" $21 ", :color=>"black", :size=>"S", :description=>"descr"} 
] }

Then @array.class.name is Hash

You can get the actual array by accessing it like so:

@actual_array = @array["C1"]

Then, @actual_array.class.name will be Array

So, taking this approach and re-writing:

@array = {"C1"=>[
  {:upc=>"51857195821952", :product_id=>"1234", :name=>"name", :price=>" $15 ", :color=>"green", :size=>"L", :description=>"descr"}, 
  {:upc=>"352353wegs", :product_id=>"456", :name=>"name2", :price=>" $21 ", :color=>"black", :size=>"S", :description=>"descr"} 
 ] }

@actual_array = @array["C1"]

@actual_array.each do |p|
  puts p[:name]
end

If you do this, you'll find that the value of the :name element will be printed neatly out.

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