{"id":1293,"date":"2015-04-08T06:00:19","date_gmt":"2015-04-08T04:00:19","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=1293"},"modified":"2015-05-01T08:44:20","modified_gmt":"2015-05-01T06:44:20","slug":"producto-de-un-numero-por-una-lista-de-numeros","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/producto-de-un-numero-por-una-lista-de-numeros\/","title":{"rendered":"Producto de un n\u00famero por una lista de n\u00fameros"},"content":{"rendered":"<p>El producto de un n\u00famero natural x por una lista de n\u00fameros naturales ys es el n\u00famero obtenido concatenando los productos de x por cada uno de los elementos de ys. Por ejemplo, el producto de 2 por [3,2,5] es 26410.<\/p>\n<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   producto :: Integer -> [Integer] -> Integer\n<\/pre>\n<p>tal que (producto x ys) es el producto de x por ys. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   producto  2 [3,2,5]  ==  6410\n   producto 10 [3,2,5]  ==  302050\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\n-- 1\u00aa definici\u00f3n (por recursi\u00f3n):\nproducto1 :: Integer -> [Integer] -> Integer\nproducto1 x ys = read (aux x ys)\n    where aux x []     = \"\"\n          aux x (y:ys) = show (x*y) ++ aux x ys\n\n-- 2\u00aa definici\u00f3n (por plegado):\nproducto2 :: Integer -> [Integer] -> Integer\nproducto2 x ys = read (aux x ys)\n    where aux x = foldr (\\y -> (++) (show (x * y))) \"\" \n\n-- 3\u00aa definici\u00f3n (por comprensi\u00f3n)\nproducto3 :: Integer -> [Integer] -> Integer\nproducto3 x ys = read (concat [show (x*y) | y <- ys])\n\n-- 4\u00aa definici\u00f3n (con map)\nproducto4 :: Integer -> [Integer] -> Integer\nproducto4 x ys = read (concat (map (show . (x*)) ys))\n\n-- 5\u00aa definici\u00f3n (con concatMap)\nproducto5 :: Integer -> [Integer] -> Integer\nproducto5 x = read . concatMap (show . (x*))\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>El producto de un n\u00famero natural x por una lista de n\u00fameros naturales ys es el n\u00famero obtenido concatenando los productos de x por cada uno de los elementos de ys. Por ejemplo, el producto de 2 por [3,2,5] es 26410. Definir la funci\u00f3n producto :: Integer -> [Integer] -> Integer tal que (producto x&#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":[12,58,94,10,90,95,6,33],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/1293"}],"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=1293"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/1293\/revisions"}],"predecessor-version":[{"id":1331,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/1293\/revisions\/1331"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=1293"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=1293"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=1293"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}