Array to XML -- Rails

Question

I have a multi-dimensional array that I'd like to use for building an xml output.

The array is storing a csv import. Where people[0][...] are the column names that will become the xml tags, and the people[...>0][...] are the values.

For instance, array contains:
people[0][0] => first-name
people[0][1] => last-name
people[1][0] => Bob
people[1][1] => Dylan
people[2][0] => Sam
people[2][1] => Shepard

XML needs to be:
<person>
  <first-name>Bob</first-name>
  <last-name>Dylan</last-name>
</person>
<person>
  <first-name>Sam</first-name>
  <last-name>Shepard</last-name>
</person>

Any help is appreciated.

If it's an import, is there any reason you're not importing to a hash instead of an array? Hash#to_xml makes things much easier because your keys are properly named. — bensie
– bensie, Commented Nov 3, 2009 at 16:31

Roel · Accepted Answer · 2009-11-03 21:05:31Z

7

I suggest using FasterCSV to import your data and to convert it into an array of hashes. That way to_xml should give you what you want:

people = []
FasterCSV.foreach("yourfile.csv", :headers => true) do |row|
 people << row.to_hash
end
people.to_xml

edited Nov 3, 2009 at 21:05

answered Nov 3, 2009 at 16:32

Roel

653 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Jeffrey Over a year ago

Got this error: undefined method `to_hash' for #<Array:0x2506840>

Phil Over a year ago

Jeffery - the above code will work if you are using the Rails environment or script/console. If you are using just the basic Ruby interpreter or irb, it will give you the above error. You will need to include some modules / libraries for xml support if using just Ruby / irb.

Jeffrey Over a year ago

I'm getting this error inside of rails. I've tried the code inside of a controller and, to test, inside of a view; both have the same error: undefined method 'to_hash'

Roel Over a year ago

Sorry about that, I edited the code. I forgot to add :headers => true. Hopefully that solves your undefined method error.

Jeffrey Over a year ago

Thanks Roel. That worked for importing a local copy of a csv file, but I'm stuck figuring out where to include the :headers => true when importing a csv file from a remote location. url = 'remote-url.com/file.csv' people = [] open(url) do |f| f.each_line do |line| FasterCSV.parse(line) do |row| people << row.to_hash end end end people.to_xml

Mike Tunnicliffe · Accepted Answer · 2009-11-03 16:46:43Z

2

There are two main ways I can think of achieving this, one using an XML serializer; the second by pushing out the raw string.

Here's an example of the second:

xml = ''
1.upto(people.size-1) do |row_idx|
  xml << "<person>\n"
  people[0].each_with_index do |column, col_idx|
    xml << "  <#{column}>#{people[row_idx][col_idx]}</#{column}>\n"
  end
  xml << "</person>\n"
end

Another way:

hash = {}
hash['person'] = []
1.upto(people.size-1) do |row_idx|
  row = {}
  people[0].each_with_index do |column, col_idx|
    row[column]=people[row_idx][col_idx]
  end
  hash['person'] << row
end
hash.to_xml

Leaving this answer here in case someone needs to convert an array like this that didn't come from a CSV file (or if they can't use FasterCSV).

edited Nov 3, 2009 at 16:46

answered Nov 3, 2009 at 16:33

Mike Tunnicliffe

10.8k3 gold badges34 silver badges46 bronze badges

3 Comments

Jeffrey Over a year ago

fd - the second one works great with the array. is there any way to add people[0][x].parameterize to the code?

Mike Tunnicliffe Over a year ago

Assuming I understand correctly, change row[column]=... to row[column.parameterize]=...

Jeffrey Over a year ago

Thanks, that does work. Though I'm moving away from using a hash because the display order is important... unless there is a work around for that? The app is using rails 2.3.4.

Henryk Konsek · Accepted Answer · 2009-11-03 18:39:19Z

1

Using Hash.to_xml is a good idea, due to its support in the core rails. It's probably the simplest way to export Hash-like data to simple XML. In most, simple cases - more complex cases requires more complex tools.

answered Nov 3, 2009 at 18:39

Henryk Konsek

9,1985 gold badges34 silver badges41 bronze badges

Comments

Jeffrey · Accepted Answer · 2009-11-05 16:11:41Z

Thanks to everyone that posted. Below is the solution that seems to work best for my needs. Hopefully others may find this useful.

This solution grabs a remote url csv file, stores it in a multi-dimensional array, then exports it as xml:

require 'rio'
require 'fastercsv'

url = 'http://remote-url.com/file.csv'
people = FasterCSV.parse(rio(url).read)

xml = ''
1.upto(people.size-1) do |row_idx|
  xml << "  <record>\n"
  people[0].each_with_index do |column, col_idx|
    xml << "    <#{column.parameterize}>#{people[row_idx][col_idx]}</#{column.parameterize}>\n"
  end
  xml << "  </record>\n"
end

There are better solutions out there, using hash.to_xml would have been great except I needed to change the csv index line to parameterize to use as a xml tag, but this code works so I'm happy.

Collectives™ on Stack Overflow

Array to XML -- Rails

4 Answers 4

5 Comments

3 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

5 Comments

3 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related