Alan, đź‘Ť
On Tuesday, September 27, 2016 at 7:38:29 AM UTC+7, Alan Thompson wrote:
>
> Hi - I was answering a question on StackOverflow, and after solving it
> using functions from clojure.core, I thought it was the prefect candidate
> for a little DataScript. Basically the user wants to do a "natural join"
> on column :obs/A, then print out pairs of :obs/value from type :x and type
> :y. The DataScript version removes a lot of tedious, manual indexing,
> filtering, unification, etc.
>
>
> (ns clj.core
> (:require [tupelo.core :as t]
> [datascript.core :as d]
> [clojure.set :as set] ))
> (t/refer-tupelo)
>
> (def data
> [ {:type :x :local/id 1, :obs/A "11", :obs/value 2.0,
> :obs/color "yellow"}
> {:type :x :local/id 2, :obs/A "12", :obs/value 4.0,
> :obs/color "blue"}
> {:type :x :local/id 3, :obs/A "13", :obs/value 3.0,
> :obs/color "green"}
> {:type :x :local/id 3, :obs/A "15", :obs/value 7.0,
> :obs/color "red"}
>
> {:type :y :local/id 2, :obs/A "11", :obs/value 7.0,
> :obs/shape "square"}
> {:type :y :local/id 2, :obs/A "13", :obs/value 4.0,
> :obs/shape "circle"}
> {:type :y :local/id 6, :obs/A "15", :obs/value 3.0,
> :obs/shape "triangle"} ] )
>
> (newline) (println "data") (pretty data)
>
> (def conn (d/create-conn {}))
> (d/transact! conn data)
>
> (def labelled-result
> (d/q '[:find ?a ?value1 ?value2
> :where
> [?ex :type :x] [?ex :obs/A ?a] [?ex :obs/value ?value1]
> [?ey :type :y] [?ey :obs/A ?a] [?ey :obs/value ?value2]
> ] @conn ))
> (newline) (println "labelled-result") (pretty labelled-result)
>
> (defn -main [& args] )
>
> ​With the result:
>
>
> ​
>
>
> data
>
> [{:type :x,
>
> :local/id 1,
>
> :obs/A "11",
>
> :obs/value 2.0,
>
> :obs/color "yellow"}
>
> {:type :x,
>
> :local/id 2,
>
> :obs/A "12",
>
> :obs/value 4.0,
>
> :obs/color "blue"}
>
> {:type :x,
>
> :local/id 3,
>
> :obs/A "13",
>
> :obs/value 3.0,
>
> :obs/color "green"}
>
> {:type :x, :local/id 3, :obs/A "15", :obs/value 7.0, :obs/color "red"}
>
> {:type :y,
>
> :local/id 2,
>
> :obs/A "11",
>
> :obs/value 7.0,
>
> :obs/shape "square"}
>
> {:type :y,
>
> :local/id 2,
>
> :obs/A "13",
>
> :obs/value 4.0,
>
> :obs/shape "circle"}
>
> {:type :y,
>
> :local/id 6,
>
> :obs/A "15",
>
> :obs/value 3.0,
>
> :obs/shape "triangle"}]
>
>
> labelled-result
>
> #{["13" 3.0 4.0] ["11" 2.0 7.0] ["15" 7.0 3.0]}
>
>
> Cool stuff.
>
> Alan​
>
>
>
>
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