How do I combine results from zip-filter queries on an xml tree in Clojure?
I want to combine the results of three zip-filter queries on an xml tree. The XML I am parsing looks like this:
<someroot>
<publication>
<contributors>
<person_name>
<surname>Surname A</surname>
</person_name>
<person_name>
<given_name>Given B</given_name>
<surname>Surname B</surname>
<suffix>Suffix B</s开发者_JAVA技巧uffix>
</person_name>
</contributors>
</publication>
</someroot>
From this example you can see that <given_name>
and <suffix>
are optional - only <surname>
is required. Here in lies my problem - if I run three separate queries the responses I get will be out of kilter with each other:
(xml-> xml :publication :contributors :person_name :given_name text)
(xml-> xml :publication :contributors :person_name :surname text)
(xml-> xml :publication :contributors :person_name :suffix text)
After running these three queries I will be left with three sequences whose cardinalities do not match; given_name
and suffix
will be length 1 while surname
will be length 2. This makes it impossible for me to combine the components of each name. I need to write a single query that will perform this name concatenation during sequence construction.
I'm looking at the very sparse documentation for clojure.contrib.zip-filter.xml
and can't figure out how I could do this (or if it is even possible). Unfortunately I am a Clojure (and Lisp) newbie! Can anyone point out how I can write a query that will concatenate three other embedded queries?
You can get all the person subtrees in one step (xml-> xmlzip :publication :contributors :person_name) then get the name parts if they exist (xml1-> personzip :surname text) and combine them to the result you want like so:
(use 'clojure.contrib.zip-filter.xml)
(defn format-name
[surname given suffix]
(str surname (if given (str ", " given)) (if suffix (str ", " suffix))))
(defn get-names
[xz]
(map (juxt
#(xml1-> % :surname text)
#(xml1-> % :given_name text)
#(xml1-> % :suffix text))
(xml-> xz :publication :contributors :person_name)))
(let [x (clojure.zip/xml-zip (clojure.xml/parse "foo.xml"))]
(map (partial apply format-name) (get-names x)))
Results in ("Surname A" "Surname B, Given B, Suffix B")
I suppose an alternative solution is to
(xml-> xml :publication :contributors :person_name)
and then process each <person_name>
later on.
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