{"id":4921,"date":"2019-04-08T06:00:32","date_gmt":"2019-04-08T04:00:32","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=4921"},"modified":"2019-04-23T18:29:16","modified_gmt":"2019-04-23T16:29:16","slug":"numeros-en-una-cadena","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/numeros-en-una-cadena\/","title":{"rendered":"N\u00fameros en una cadena"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\"> \n   numeros :: String -> [Int]\n<\/pre>\n<p>tal que (numeros cs) es la lista de los n\u00fameros enteros no negativos de la cadena cs. Por ejemplo,<\/p>\n<pre lang=\"text\"> \n   \u03bb> numeros \"Esta cadena tiene 3 numeros: el 16 y el 2019 solamente.\" \n   [3,16,2019]\n   \u03bb> numeros \"Esta cadena tiene 3 numeros naturales: -2 m\u00e1s 2 es 0\" \n   [3,2,0]\n   \u03bb> numeros \"Esta cadena tiene 1 numero natural: 2.5 no es entereo\" \n   [1]\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Data.Char  (isDigit)\n\n-- 1\u00aa definici\u00f3n\n-- =============\n\nnumeros :: String -> [Int]\nnumeros cs = map read (filter esNumero (words cs))\n\n-- (esNumero cs) se verifica si la cadena no vac\u00eda cs representa\n-- un n\u00famero entero. Por ejemplo,\n--    esNumero \"2019\"  ==  True\n--    esNumero \"20.9\"  ==  False\n--    esNumero \"201a\"  ==  False\nesNumero :: String -> Bool\nesNumero = all (`elem` ['0'..'9'])\n\n-- 2\u00aa soluci\u00f3n\n-- ===========\n\nnumeros2 :: String -> [Int]\nnumeros2 cs = map read (filter (all isDigit) (words cs))\n\n-- 3\u00aa soluci\u00f3n\n-- ===========\n\nnumeros3 :: String -> [Int]\nnumeros3 = map read . filter (all isDigit) . words\n<\/pre>\n<h4>Pensamiento<\/h4>\n<blockquote><p>\nTu profec\u00eda, poeta.<br \/>\n&#8212; Ma\u00f1ana hablar\u00e1n los mudos:<br \/>\nel coraz\u00f3n y la piedra.<\/p>\n<p>Antonio Machado\n<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n numeros :: String -> [Int] tal que (numeros cs) es la lista de los n\u00fameros enteros no negativos de la cadena cs. Por ejemplo, \u03bb> numeros \u00abEsta cadena tiene 3 numeros: el 16 y el 2019 solamente.\u00bb [3,16,2019] \u03bb> numeros \u00abEsta cadena tiene 3 numeros naturales: -2 m\u00e1s 2 es 0\u00bb [3,2,0]&#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":[41,58,26,38,101,246,10,11,95,478,75,255,132],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4921"}],"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=4921"}],"version-history":[{"count":4,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4921\/revisions"}],"predecessor-version":[{"id":4951,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/4921\/revisions\/4951"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=4921"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=4921"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=4921"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}