luciano/clojure-koans
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Finished koans 12

Browse source
This commit is contained in:
Matt Davidson 2022-11-05 10:20:47 +00:00
parent 3e761f927a
commit 2bd286b9aa
1 changed files with 8 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
src/koans/12_sequence_comprehensions.clj
View file

@ -3,34 +3,28 @@
(meditations
"Sequence comprehensions can bind each element in turn to a symbol"
(= __
(for [x (range 6)]
x))
(= '(0 1 2 3 4 5)
(for [x (range 6)] x))
"They can easily emulate mapping"
(= '(0 1 4 9 16 25)
(map (fn [x] (* x x))
(range 6))
(for [x (range 6)]
__))
(map (fn [x] (* x x)) (range 6))
(for [x (range 6)] (* x x)))
"And also filtering"
(= '(1 3 5 7 9)
(filter odd? (range 10))
(for [x __ :when (odd? x)]
(for [x (range 10) :when (odd? x)]
x))
"Combinations of these transformations are trivial"
(= '(1 9 25 49 81)
(map (fn [x] (* x x))
(filter odd? (range 10)))
(for [x (range 10) :when __]
__))
(map (fn [x] (* x x)) (filter odd? (range 10)))
(for [x (range 10) :when (odd? x)] (* x x)))
"More complex transformations simply take multiple binding forms"
(= [[:top :left] [:top :middle] [:top :right]
[:middle :left] [:middle :middle] [:middle :right]
[:bottom :left] [:bottom :middle] [:bottom :right]]
(for [row [:top :middle :bottom]
column [:left :middle :right]]
__)))
column [:left :middle :right]] [row column])))