{"id":4944,"date":"2019-04-22T07:48:05","date_gmt":"2019-04-22T05:48:05","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=4944"},"modified":"2019-05-01T08:49:21","modified_gmt":"2019-05-01T06:49:21","slug":"elementos-no-repetidos","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/elementos-no-repetidos\/","title":{"rendered":"Elementos no repetidos"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\"> \n   noRepetidos :: Eq a => [a] -> [a]\n<\/pre>\n<p>tal que (noRepetidos xs) es la lista de los elementos no repetidos de la lista xs. Por ejemplo,<\/p>\n<pre lang=\"text\"> \n   noRepetidos [3,2,5,2,4,7,3]  ==  [5,4,7]\n   noRepetidos \"noRepetidos\"    ==  \"nRptids\"\n   noRepetidos \"Roma\"           ==  \"Roma\"\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Test.QuickCheck\n\n-- 1\u00aa soluci\u00f3n\n-- ===========\n\nnoRepetidos :: Eq a => [a] -> [a]\nnoRepetidos xs = \n  [x | x <- xs, ocurrencias x xs == 1]\n  \n-- (ocurrencias x ys) es el n\u00famero de ocurrencias de x en ys. Por\n-- ejemplo,\n--    ocurrencias 3 [3,2,5,2,4,7,3]  ==  2\n--    ocurrencias 5 [3,2,5,2,4,7,3]  ==  1\nocurrencias :: Eq a => a -> [a] -> Int\nocurrencias x ys = \n  length [y | y <- ys, y == x]\n\n-- 2\u00aa soluci\u00f3n\n-- ===========\nnoRepetidos2 :: Eq a => [a] -> [a]\nnoRepetidos2 [] = []\nnoRepetidos2 (x:xs) | elem x xs = noRepetidos2 [y | y <- xs, y \/= x]\n                    | otherwise = x : noRepetidos2 xs\n\n-- Equivalencia\n-- ============\n\n-- La propiedad de equivalencia es\nprop_equivalencia :: [Int] -> Bool\nprop_equivalencia xs =\n  noRepetidos xs == noRepetidos2 xs\n\n-- La comprobaci\u00f3n es\n--    ghci> quickCheck prop_equivalencia\n--    +++ OK, passed 100 tests.\n<\/pre>\n<h4>Pensamiento<\/h4>\n<blockquote><p>\nY en perfecto rimo<br \/>\n&#8212; as\u00ed a la vera del agua<br \/>\nel doble chopo del r\u00edo.<\/p>\n<p>Antonio Machado\n<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n noRepetidos :: Eq a => [a] -> [a] tal que (noRepetidos xs) es la lista de los elementos no repetidos de la lista xs. Por ejemplo, noRepetidos [3,2,5,2,4,7,3] == [5,4,7] noRepetidos \u00abnoRepetidos\u00bb == \u00abnRptids\u00bb noRepetidos \u00abRoma\u00bb == \u00abRoma\u00bb Soluciones import Test.QuickCheck &#8212; 1\u00aa soluci\u00f3n &#8212; =========== noRepetidos :: Eq a => [a]&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"footnotes":"","_jetpack_memberships_contains_paid_content":false},"categories":[5],"tags":[8,26,28,6,146],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4944"}],"collection":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/comments?post=4944"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4944\/revisions"}],"predecessor-version":[{"id":4987,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4944\/revisions\/4987"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=4944"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=4944"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=4944"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}