Basic use of the Clojure tablecloth library

Tablecloth Use

(ns weather.core
  (:require [tablecloth.api :as api])
  (:gen-class))

(defonce weather
  (api/dataset "https://vega.github.io/vega-lite/examples/data/seattle-weather.csv"
               {:key-fn keyword}))

(defn avg [data]
  (double (/ (reduce + data) (count data))))

(comment
  ;; Count rows in a dataset
  (api/row-count weather)
  ;; Count columns in a dataset
  (api/column-count weather)
  ;; Get the shape of the dataset (rows and columns)
  (api/shape weather)
  ;; Get the column names
  (api/column-names weather)
  ;; Get a summary of the data over the columns
  (api/info weather)

  ;; Group the data by weather condition (sun, rain, snow, ...)
  (api/group-by weather [:weather])
  ;; Group the data by weather condition, and print it
  (-> (api/group-by weather [:weather])
      (api/print-dataset {:print-line-policy :repl}))
  ;; Group the data into two groups:
  ;;   days with a min temp less than zero
  ;;   days with a positive min temp
  (-> (api/group-by weather #(< (:temp_min %) 0))
      (api/rows :as-maps))
  ;; Group the data by weather condition, and add two columns
  ;;   average min temp for the group
  ;;   average max temp for the group
  (-> (api/group-by weather [:weather])
      (api/aggregate {:avg_min #(avg (:temp_min %))
                      :avg_max #(avg (:temp_max %))}))
  ;; Save a new dataset that has had columns added to a csv text file
  (-> (api/group-by weather [:weather])
      (api/aggregate {:avg_min #(avg (:temp_min %))
                      :avg_max #(avg (:temp_max %))})
      (api/write! "my-weather-update.csv"))
  )