Data commit

Task/Align-columns/Clojure/align-columns.clj

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+(ns rosettacode.align-columns
+  (:require [clojure.contrib.string :as str]))
+
+(def data "Given$a$text$file$of$many$lines,$where$fields$within$a$line$
+are$delineated$by$a$single$'dollar'$character,$write$a$program
+that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$
+column$are$separated$by$at$least$one$space.
+Further,$allow$for$each$word$in$a$column$to$be$either$left$
+justified,$right$justified,$or$center$justified$within$its$column.")
+
+(def table (map #(str/split #"\$" %) (str/split-lines data)))
+
+(defn col-width [n table] (reduce max (map #(try (count (nth % n))
+                                               (catch Exception _  0))
+                                           table)))
+(defn spaces [n] (str/repeat n " "))
+(defn add-padding
+  "if the string is too big turncate it, else return a string with padding"
+  [string width justification]
+  (if (>= (count string) width) (str/take width string)
+      (let [pad-len (int (- width (count string))) ;we don't want rationals
+            half-pad-len (int (/ pad-len 2))]
+        (case justification
+              :right (str (spaces pad-len) string)
+              :left  (str string (spaces pad-len))
+              :center (str (spaces half-pad-len) string (spaces (- pad-len half-pad-len)))))))
+
+(defn aligned-table
+  "get the width of each column, then generate a new table with propper padding for eath item"
+  ([table justification]
+  (let [col-widths (map #(+ 2 (col-width % table)) (range (count(first table))))]
+    (map
+     (fn [row] (map #(add-padding %1 %2 justification) row col-widths))
+     table))))
+
+(defn print-table
+  [table]
+  (do (println)
+      (print (str/join "" (flatten (interleave table (repeat "\n")))))))
+
+(print-table (aligned-table table :center))