Merge hash into arrays while using loop

Question

Currently I am getting an array of hashes by doing this:

f = File.open("public/odds/test.xml")
xml = Nokogiri::XML(f)
path = "//demo/test1/test"
xml.xpath(path).map do |x|
{'country' => x.parent}
end

A sample of my result for this:

[{"country"=>"france"}, {"country"=>"singapore"}, {"country"=>"thailand"}]

Now as I have different xml files, I am doing a loop to go through all the files:

@files = ['a', 'b', 'c']
@files.each do |file|
f = File.open("public/odds/#{file}.xml)
xml = Nokogiri::XML(f)
path = "//demo/test1/test"
xml.xpath(path).map do |x|
{'country' => x.parent}
end

As it is looping through each file, I expect to get 3 different results like this [{"country"=>"france"}, {"country"=>"singapore"}, {"country"=>"thailand"}]. How can I merge them together so that they are in 1 array?

Your code is invalid.

sawa
– sawa

2015-10-12 08:37:28 +00:00
Commented Oct 12, 2015 at 8:37 — sawa
– sawa, Commented Oct 12, 2015 at 8:37

Aleksei Matiushkin · Accepted Answer · 2015-10-12 06:50:47Z

1

Do you want to inject results? Array#inject comes to the rescue:

path = "//demo/test1/test"
#      ⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓
result = @files.inject([]) do |memo, file|
  File.open("public/odds/#{file}.xml") do |f|
    xml = Nokogiri::XML(f)
#   ⇓⇓⇓⇓⇓⇓⇓
    memo << xml.xpath(path).map do |x|
              {'country' => x.parent}
            end
  end
end.flatten
puts result
#⇒ [ {"country"=>"france"}, {"country"=>"singapore"}, {"country"=>"thailand"},
#     ...
#     ... ]

Also, consider to use a File#open with a block. In your code the opened files remain unclosed, while the block will close them automatically on return. Whether one still wants to use File#new (≡ File#open without block,) one should explicitly call f.close as soon as the file is not needed anymore.

edited Oct 12, 2015 at 6:50

answered Oct 12, 2015 at 5:58

Aleksei Matiushkin

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2 Comments

pyfl88 Over a year ago

Thanks. I would like to mark this as the correct answer, but I wonder why my result return as

[ [{"country"=>"france"}, {"country"=>"singapore"}, {"country"=>"thailand"}], [{"country"=>"france"}, {"country"=>"singapore"}, {"country"=>"thailand"}],[{"country"=>"france"}, {"country"=>"singapore"}, {"country"=>"thailand"}]]

?

pyfl88 Over a year ago

I used inject method along with flatten to solve my problem. Thanks

Vishal Jain · Accepted Answer · 2015-10-12 06:02:30Z

1

I think you try this way. just declare new array an push all hash inside that array arr << {'country' => x.parent} and replace your map by each loop

 arr=[]
    @files = ['a', 'b', 'c']
    @files.each do |file|
    f = File.open("public/odds/#{file}.xml)
    xml = Nokogiri::XML(f)
    path = "//demo/test1/test"
    xml.xpath(path).each do |x|
       arr << {'country' => x.parent}
    end
end

    return arr

edited Oct 12, 2015 at 6:02

answered Oct 12, 2015 at 5:55

Vishal Jain

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4 Comments

Vishal Jain Over a year ago

i am considering it as function so return is used there. otherwise no need to used it. Just used arr variable

Aleksei Matiushkin Over a year ago

It is still ruby, not php. Function does not need to use return unless there is a quick-return pattern used for preliminary checks.

Vishal Jain Over a year ago

yes sure but i think more readble for OP so used return otherwise no need. here for more explanation to op so not using quick return.

pyfl88 Over a year ago

Thanks. This is also a correct answer, but I chose to use the inject method.

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