The ruby csv library requires quite a bit more typing, and the documentation for it is easy to misunderstand.
One of my primary needs, is often data wrangling. Changing the contents of a csv file for use in another framework, whether it’s reverse coordinates, stripping unwanted columns, or adding needed columns to the data, and I always trip up on how to dump the changed CSV after manipulating it.
As a reminder to myself, and maybe a hint to others, I’ve include the proper way to dump out your arr_of_arrs, once you’ve manipulated it as you will,
It makes XML easy to use and easy to query. Gone are the days of parsing things with a SaxParser unless you’re really hard up for control of you text.
Also, I love the Ruby Nokogiri Gem.
XML is like violence – if it doesn’t solve your problems, you are not using enough of it.
– Nokogiri docs
But I do have to say that there is a lack of good examples and documentation for anything particularly advanced. I found a working solution to my issue, but thought I’d paste here what I wanted to do versus what I ended up doing.
I’d like to grab two elements that include “Cover” in the tag, and then operate on each of them.
Nokogiri’s use of Xpath easily allows the first query expression like so: price_xml = doc_xml.xpath('Container/Set/*[contains(name(), "Cover")]')
I’ve selected all the elements (using *) in Set, and then used an Xpath Expression function:
contains, in order to specify that Adult must be in the name. This returns two Nokogiri XML Nodes in Nodeset.
What I wanted to do was then select one of these elements based on a pattern in the tagname use my favorite tool, Xpath.
But I just couldn’t get Nokogiri to give it to me, and several solutions ending up selecting way more than the 1 element I wanted. (Because the nodes in the Nodeset still contain relationships with their parents)