From 0b3c97ce36fa24269d8d38411a52c2085f4c3723 Mon Sep 17 00:00:00 2001 From: Oli Clive-Griffin Date: Thu, 3 Jun 2021 14:02:37 +1200 Subject: [PATCH] maps done --- src/koans/06_maps.clj | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/src/koans/06_maps.clj b/src/koans/06_maps.clj index c2e5d9a..33ba18c 100644 --- a/src/koans/06_maps.clj +++ b/src/koans/06_maps.clj @@ -3,60 +3,60 @@ (meditations "Don't get lost when creating a map" - (= {:a 1 :b 2} (hash-map :a 1 __ __)) + (= {:a 1 :b 2} (hash-map :a 1 :b 2)) "A value must be supplied for each key" - (= {:a 1} (hash-map :a __)) + (= {:a 1} (hash-map :a 1)) "The size is the number of entries" - (= __ (count {:a 1 :b 2})) + (= 2 (count {:a 1 :b 2})) "You can look up the value for a given key" - (= __ (get {:a 1 :b 2} :b)) + (= 2 (get {:a 1 :b 2} :b)) "Maps can be used as functions to do lookups" - (= __ ({:a 1 :b 2} :a)) + (= 1 ({:a 1 :b 2} :a)) "And so can keywords" - (= __ (:a {:a 1 :b 2})) + (= 1 (:a {:a 1 :b 2})) "But map keys need not be keywords" - (= __ ({2010 "Vancouver" 2014 "Sochi" 2018 "PyeongChang"} 2014)) + (= "Sochi" ({2010 "Vancouver" 2014 "Sochi" 2018 "PyeongChang"} 2014)) "You may not be able to find an entry for a key" - (= __ (get {:a 1 :b 2} :c)) + (= nil (get {:a 1 :b 2} :c)) "But you can provide your own default" - (= __ (get {:a 1 :b 2} :c :key-not-found)) + (= :key-not-found (get {:a 1 :b 2} :c :key-not-found)) "You can find out if a key is present" - (= __ (contains? {:a nil :b nil} :b)) + (= true (contains? {:a nil :b nil} :b)) "Or if it is missing" - (= __ (contains? {:a nil :b nil} :c)) + (= false (contains? {:a nil :b nil} :c)) "Maps are immutable, but you can create a new and improved version" - (= {1 "January" 2 __} (assoc {1 "January"} 2 "February")) + (= {1 "January" 2 "February"} (assoc {1 "January"} 2 "February")) "You can also create a new version with an entry removed" - (= {__ __} (dissoc {1 "January" 2 "February"} 2)) + (= {1 "January"} (dissoc {1 "January" 2 "February"} 2)) "Create a new map by merging" - (= {:a 1 :b 2 __ __} (merge {:a 1 :b 2} {:c 3})) + (= {:a 1 :b 2 :c 3} (merge {:a 1 :b 2} {:c 3})) "Specify how to handle entries with same keys when merging" - (= {:a 1 :b __ :c 3} (merge-with + {:a 1 :b 1} {:b 1 :c 3})) + (= {:a 1 :b 2 :c 3} (merge-with + {:a 1 :b 1} {:b 1 :c 3})) "Often you will need to get the keys, but the order is undependable" - (= (list __ __ __) + (= (list 2010 2014 2018) (sort (keys { 2014 "Sochi" 2018 "PyeongChang" 2010 "Vancouver"}))) "You can get the values in a similar way" - (= (list __ __ __) + (= (list "PyeongChang" "Sochi" "Vancouver") (sort (vals {2010 "Vancouver" 2014 "Sochi" 2018 "PyeongChang"}))) "You can even iterate over the map entries as a seq" - (= {:a __ :b __} + (= {:a 2 :b 3} (into {} (map (fn [[k v]] [k (inc v)])