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blancohugo's solution

to Anagram in the Clojure Track

Published at Sep 12 2019 · 1 comment
Test suite

Given a word and a list of possible anagrams, select the correct sublist.

Given "listen" and a list of candidates like "enlists" "google" "inlets" "banana" the program should return a list containing "inlets".


Inspired by the Extreme Startup game https://github.com/rchatley/extreme_startup

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(ns anagram-test
  (:require [clojure.test :refer [deftest is]]

(deftest no-matches
  (is (= []
         (anagram/anagrams-for "diaper" ["hello" "world" "zombies" "pants"]))))

(deftest detect-simple-anagram
  (is (= ["tan"] (anagram/anagrams-for "ant" ["tan" "stand" "at"]))))

(deftest does-not-confuse-different-duplicates
  (is (= [] (anagram/anagrams-for "galea" ["eagle"]))))

(deftest eliminate-anagram-subsets
  (is (= [] (anagram/anagrams-for "good" ["dog" "goody"]))))

(deftest detect-anagram
  (is (= ["inlets"]
         (let [coll ["enlists" "google" "inlets" "banana"]]
           (anagram/anagrams-for "listen" coll)))))

(deftest multiple-anagrams
  (is (= ["gallery" "regally" "largely"]
         (let [coll ["gallery" "ballerina" "regally"
                     "clergy"  "largely"   "leading"]]
           (anagram/anagrams-for "allergy" coll)))))

(deftest case-insensitive-anagrams
  (is (= ["Carthorse"]
         (let [coll ["cashregister" "Carthorse" "radishes"]]
           (anagram/anagrams-for "Orchestra" coll)))))

(deftest word-is-not-own-anagram
  (is (= [] (anagram/anagrams-for "banana" ["banana"]))))

(deftest capital-word-is-not-own-anagram
  (is (= [] (anagram/anagrams-for "BANANA" ["banana"]))))
(ns anagram
  (:require [clojure.string :as str]))

(defn remove-char [word index]
    (>= index (count word)) word
    (empty? word) word
    :else (str (subs word 0 index)
               (subs word (inc index)))))

(defn extract-letters [word letters]
  (if (empty? letters)
    (let [index (str/index-of word (first letters))]
      (if index
        (recur (remove-char word index) (rest letters))
        (recur word (rest letters))))))

(defn anagram? [word prospect]
  (let [word (str/lower-case word)
        prospect (str/lower-case prospect)]
      (or (empty? word) (empty? prospect)) false
      (= word prospect) false
      :else (and (empty? (extract-letters word (seq prospect)))
                 (empty? (extract-letters prospect (seq word)))))))

(defn anagrams-for [word prospect-list]
  (filter #(anagram? word %) prospect-list))

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Avatar of blancohugo

I just realized that I could have done this with frequencies.

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