{"id":531,"date":"2014-11-01T07:34:35","date_gmt":"2014-11-01T05:34:35","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=531"},"modified":"2021-04-25T17:08:23","modified_gmt":"2021-04-25T15:08:23","slug":"elementos-no-repetidos-2014","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/elementos-no-repetidos-2014\/","title":{"rendered":"Elementos no repetidos"},"content":{"rendered":"<h4>Enunciado<\/h4>\n<pre lang=\"text\">\n-- Definir la funci\u00f3n \n--    noRepetidos :: Eq a => [a] -> [a]\n-- tal que (noRepetidos xs) es la lista de los elementos no repetidos de\n-- la lista xs. Por ejemplo,\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 (por comprensi\u00f3n):\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 definici\u00f3n (por recursi\u00f3n):\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-- 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","protected":false},"excerpt":{"rendered":"<p>Enunciado &#8212; Definir la funci\u00f3n &#8212; noRepetidos :: Eq a => [a] -> [a] &#8212; tal que (noRepetidos xs) es la lista de los elementos no repetidos de &#8212; la lista xs. Por ejemplo, &#8212; noRepetidos [3,2,5,2,4,7,3] == [5,4,7] &#8212; noRepetidos \u00abnoRepetidos\u00bb == \u00abnRptids\u00bb &#8212; noRepetidos \u00abRoma\u00bb == \u00abRoma\u00bb Soluciones import Test.QuickCheck &#8212; 1\u00aa soluci\u00f3n&#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\/531"}],"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=531"}],"version-history":[{"count":7,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/531\/revisions"}],"predecessor-version":[{"id":750,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/531\/revisions\/750"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=531"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=531"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=531"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}