Ruby Arrays: select(), collect(), and map()

EDIT: I just realized you want to filter details, which is an array of hashes. In that case you could do

details.reject { |item| item[:qty].empty? }

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The inner data structure itself is not an Array, but a Hash. You can also use select here, but the block is given the key and value in this case:

irb(main):001:0> h = {:sku=>"507772-B21", :desc=>"HP 1TB 3G SATA 7.2K RPM LFF (3 .", :qty=>"", :qty2=>"1", :price=>"5,204.34 P"}
irb(main):002:0> h.select { |key, value| !value.empty? }
=> {:sku=>"507772-B21", :desc=>"HP 1TB 3G SATA 7.2K RPM LFF (3 .", 
    :qty2=>"1", :price=>"5,204.34 P"}

Or using reject, which is the inverse of select (excludes all items for which the given condition holds):

h.reject { |key, value| value.empty? }

Note that this is Ruby 1.9. If you have to maintain compatibility with 1.8, you could do:

Hash[h.reject { |key, value| value.empty? }]

It looks like details is an array of hashes. So item inside of your block will be the whole hash. Therefore, to check the :qty key, you'd do something like the following:

details.select{ |item| item[:qty] != "" }

That will give you all items where the :qty key isn't an empty string.

official select documentation