Data extraction from Map

Programming Technology 　ICT Technology 　Front-end development in Javascript 　Web Technology 　Clojure and Functional Programming　 Digital Transformation

When we process data in Clojure, we often use Map data access. For example, let’s say you have a postgresql database output or a CSV data map like the one below.

(def output-text [{:id 1 :text "aaa" :tag true}
                 { :id 2 :text "bbb" :tag false}
                 { :id 3 :text "ccc" :tag true}
                 { :id 4 :text "ddd" :tag true}
                 { :id 5 :text "eee" :tag false}])

If you want to extract arbitrary :text data from this

(defn output-data [n]
  (->> output-text
     (filter #(= (:text %) n))
      first))

if we take

(output-data "ccc") 
->  {:id 3 :text "ccc" :tag true}

If you use the “re-find” function instead of the “=” function, you can do a simple full-text search as follows. If you use the “re-find” function instead of the “=” function, you can do a simple full-text search like the following.

(defn search-data [n]
       (filter #(re-find  (re-pattern n) (:text %)) output-text))

Now, for a more complex nested map structure like the output of rdf store (e.g. generated from xml like this

<root>
  <records>
    <record id="1">record01</record>
    <record id="2">record02</record>
  </records>
  <record id="3">record03</record>
</root>

Using clojure.data.zip, set the leiningen dependency as follows

[org.clojure/data.zip "1.0.0"]

The data is extracted in the following way.

(use 'clojure.data.zip.xml)
(require ['clojure.xml :as 'xml])
(require ['clojure.zip :as 'zip])

(xml-> (zip/xml-zip (xml/parse "in.xml")) :records :record text)
; -> ("record01" "record02")

(xml-> (zip/xml-zip (xml/parse "in.xml")) :record text)
; -> ("record03")

(xml-> (zip/xml-zip (xml/parse "in.xml")) :record (attr :id))
; -> ("3")

For data with a complex structure, it would be simpler to use SAPRQL or other queries to get processed data directly from the DB via the API.

Chinoba

Chinoba

Intelligence as Relationship

Research Platform

founded by

Masao Watanabe

AI Systems Architecture
Decision Trace
Human–AI Coordination
Algorithmic Governance