{"id":6763,"date":"2022-03-16T06:00:02","date_gmt":"2022-03-16T04:00:02","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=6763"},"modified":"2022-03-23T09:37:46","modified_gmt":"2022-03-23T07:37:46","slug":"alfabeto-comenzando-en-un-caracter","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/alfabeto-comenzando-en-un-caracter\/","title":{"rendered":"Alfabeto comenzando en un car\u00e1cter"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   alfabetoDesde :: Char -> String\n<\/pre>\n<p>tal que <code>(alfabetoDesde c)<\/code> es el alfabeto, en min\u00fascula, comenzando en el car\u00e1cter <code>c<\/code>, si <code>c<\/code> es una letra min\u00fascula y comenzando en &#8216;a&#8217;, en caso contrario. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   alfabetoDesde 'e'  ==  \"efghijklmnopqrstuvwxyzabcd\"\n   alfabetoDesde 'a'  ==  \"abcdefghijklmnopqrstuvwxyz\"\n   alfabetoDesde '7'  ==  \"abcdefghijklmnopqrstuvwxyz\"\n   alfabetoDesde '{'  ==  \"abcdefghijklmnopqrstuvwxyz\"\n   alfabetoDesde 'B'  ==  \"abcdefghijklmnopqrstuvwxyz\"\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Data.Char (isLower, isAscii)\nimport Test.QuickCheck\n\n-- 1\u00aa soluci\u00f3n\nalfabetoDesde1 :: Char -> String\nalfabetoDesde1 c =\n  dropWhile (<c) ['a'..'z'] ++ takeWhile (<c) ['a'..'z']\n\n-- 2\u00aa soluci\u00f3n\nalfabetoDesde2 :: Char -> String\nalfabetoDesde2 c = ys ++ xs\n  where (xs,ys) = span (<c) ['a'..'z']\n\n-- 3\u00aa soluci\u00f3n\nalfabetoDesde3 :: Char -> String\nalfabetoDesde3 c = ys ++ xs\n  where (xs,ys) = break (==c) ['a'..'z']\n\n-- 4\u00aa soluci\u00f3n\nalfabetoDesde4 :: Char -> String\nalfabetoDesde4 c\n  | 'a' <= c &#038;&#038; c <= 'z' = [c..'z'] ++ ['a'..pred c]\n  | otherwise            = ['a'..'z']\n\n-- 5\u00aa soluci\u00f3n\nalfabetoDesde5 :: Char -> String\nalfabetoDesde5 c\n  | isLower c = [c..'z'] ++ ['a'..pred c]\n  | otherwise = ['a'..'z']\n\n-- Comprobaci\u00f3n de equivalencia\n-- ============================\n\n-- La propiedad es\nprop_alfabetoDesde :: Property\nprop_alfabetoDesde =\n  forAll (arbitrary `suchThat` isAscii) $ \\c ->\n  all (== alfabetoDesde1 c)\n      [f c | f <- [alfabetoDesde2,\n                   alfabetoDesde3,\n                   alfabetoDesde4,\n                   alfabetoDesde5]]\n\n\n-- La comprobaci\u00f3n es\n--    \u03bb> quickCheck prop_alfabetoDesde\n--    +++ OK, passed 100 tests.\n<\/pre>\n<p>El c\u00f3digo se encuentra en <a href=\"https:\/\/github.com\/jaalonso\/Exercitium\/blob\/main\/src\/Alfabeto_desde.hs\">GitHub<\/a>.<\/p>\n<p>La elaboraci\u00f3n de las soluciones se muestra en el siguiente v\u00eddeo<\/p>\n<p><iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/4eBJi5_8qM0\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n alfabetoDesde :: Char -> String tal que (alfabetoDesde c) es el alfabeto, en min\u00fascula, comenzando en el car\u00e1cter c, si c es una letra min\u00fascula y comenzando en &#8216;a&#8217;, en caso contrario. Por ejemplo, alfabetoDesde &#8216;e&#8217; == \u00abefghijklmnopqrstuvwxyzabcd\u00bb alfabetoDesde &#8216;a&#8217; == \u00ababcdefghijklmnopqrstuvwxyz\u00bb alfabetoDesde &#8216;7&#8217; == \u00ababcdefghijklmnopqrstuvwxyz\u00bb alfabetoDesde &#8216;{&#8216; == \u00ababcdefghijklmnopqrstuvwxyz\u00bb alfabetoDesde &#8216;B&#8217;&#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":[2],"tags":[8,504,11],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/6763"}],"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=6763"}],"version-history":[{"count":6,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/6763\/revisions"}],"predecessor-version":[{"id":6822,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/6763\/revisions\/6822"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=6763"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=6763"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=6763"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}