{"id":8488,"date":"2024-02-14T06:00:16","date_gmt":"2024-02-14T04:00:16","guid":{"rendered":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=8488"},"modified":"2024-02-23T10:43:17","modified_gmt":"2024-02-23T08:43:17","slug":"14-feb-24","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/14-feb-24\/","title":{"rendered":"Suma de cadenas"},"content":{"rendered":"<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   sumaCadenas :: String -> String -> String\n<\/pre>\n<p>tal que <code>sumaCadenas xs ys<\/code> es la cadena formada por el n\u00famero  que es la suma de los n\u00fameros enteros cuyas cadenas que lo representan son <code>xs<\/code> e <code>ys<\/code>; adem\u00e1s, se supone que la cadena vac\u00eda representa al cero. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   sumaCadenas \"2\"   \"6\"  == \"8\"\n   sumaCadenas \"14\"  \"2\"  == \"16\"\n   sumaCadenas \"14\"  \"-5\" == \"9\"\n   sumaCadenas \"-14\" \"-5\" == \"-19\"\n   sumaCadenas \"5\"   \"-5\" == \"0\"\n   sumaCadenas \"\"    \"5\"  == \"5\"\n   sumaCadenas \"6\"   \"\"   == \"6\"\n   sumaCadenas \"\"    \"\"   == \"0\"\n<\/pre>\n<p><!--more--><\/p>\n<p><a name=\"haskell\"><\/a><\/p>\n<h2>1. Soluciones en Haskell<\/h2>\n<pre lang=\"haskell\">\nmodule Suma_de_cadenas where\nimport Test.Hspec (Spec, describe, hspec, it, shouldBe)\n\n-- 1\u00aa soluci\u00f3n\n-- ===========\n\nsumaCadenas1 :: String -> String -> String\nsumaCadenas1 xs ys =\n  show (sum (map read (filter (not . null) [xs, ys])))\n\n-- 2\u00aa soluci\u00f3n\n-- ===========\n\nsumaCadenas2 :: String -> String -> String\nsumaCadenas2 =\n  ((show . sum . map read . filter (not . null)) .) . (. return) . (:)\n\n-- 3\u00aa soluci\u00f3n\n-- ===========\n\nsumaCadenas3 :: String -> String -> String\nsumaCadenas3 \"\" \"\" = \"0\"\nsumaCadenas3 \"\" ys = ys\nsumaCadenas3 xs \"\" = xs\nsumaCadenas3 xs ys = show (read xs + read ys)\n\n-- 4\u00aa soluci\u00f3n\n-- ===========\n\nsumaCadenas4 :: String -> String -> String\nsumaCadenas4 xs ys = show (numero xs + numero ys)\n\n-- (numero xs) es el n\u00famero entero representado por la cadena xs\n-- suponiendo que la cadena vac\u00eda representa al cero.. Por ejemplo,\n--    numero \"12\"   ==  12\n--    numero \"-12\"  ==  -12\n--    numero \"0\"    ==  0\n--    numero \"\"     ==  0\nnumero :: String -> Int\nnumero \"\" = 0\nnumero xs = read xs\n\n-- Verificaci\u00f3n\n-- ============\n\nverifica :: IO ()\nverifica = hspec spec\n\nspecG :: (String -> String -> String) -> Spec\nspecG sumaCadenas = do\n  it \"e1\" $\n    sumaCadenas \"2\"   \"6\"  `shouldBe` \"8\"\n  it \"e2\" $\n    sumaCadenas \"14\"  \"2\"  `shouldBe` \"16\"\n  it \"e3\" $\n    sumaCadenas \"14\"  \"-5\" `shouldBe` \"9\"\n  it \"e4\" $\n    sumaCadenas \"-14\" \"-5\" `shouldBe` \"-19\"\n  it \"e5\" $\n    sumaCadenas \"5\"   \"-5\" `shouldBe` \"0\"\n  it \"e6\" $\n    sumaCadenas \"\"    \"5\"  `shouldBe` \"5\"\n  it \"e7\" $\n    sumaCadenas \"6\"   \"\"   `shouldBe` \"6\"\n  it \"e8\" $\n    sumaCadenas \"\"    \"\"   `shouldBe` \"0\"\n\nspec :: Spec\nspec = do\n  describe \"def. 1\" $ specG sumaCadenas1\n  describe \"def. 2\" $ specG sumaCadenas2\n  describe \"def. 3\" $ specG sumaCadenas3\n  describe \"def. 4\" $ specG sumaCadenas4\n\n-- La verificaci\u00f3n es\n--    \u03bb> verifica\n--\n--    32 examples, 0 failures\n<\/pre>\n<p><a name=\"python\"><\/a><\/p>\n<h2>2. Soluciones en Python<\/h2>\n<pre lang=\"python\">\n# 1\u00aa soluci\u00f3n\n# ===========\n\ndef sumaCadenas1(xs: str, ys: str) -> str:\n    return str(sum(map(int, filter(lambda x: x != '', [xs, ys]))))\n\n# 2\u00aa soluci\u00f3n\n# ===========\n\ndef sumaCadenas2(xs: str, ys: str) -> str:\n    if xs == \"\" and ys == \"\":\n        return \"0\"\n    if xs == \"\":\n        return ys\n    if ys == \"\":\n        return xs\n    return str(int(xs) + int(ys))\n\n# 3\u00aa soluci\u00f3n\n# ===========\n\n# numero(xs) es el n\u00famero entero representado por la cadena xs\n# suponiendo que la cadena vac\u00eda representa al cero.. Por ejemplo,\n#    numero \"12\"   ==  12\n#    numero \"-12\"  ==  -12\n#    numero \"0\"    ==  0\n#    numero \"\"     ==  0\ndef numero(s: str) -> int:\n    if not s:\n        return 0\n    return int(s)\n\ndef sumaCadenas3(xs: str, ys: str) -> str:\n    return str(numero(xs) + numero(ys))\n\n# 4\u00aa soluci\u00f3n\n# ===========\n\ndef sumaCadenas4(xs: str, ys: str) -> str:\n    x = int(xs or \"0\")\n    y = int(ys or \"0\")\n    return str(x + y)\n\n# Verificaci\u00f3n\n# ============\n\ndef test_sumaCadenas() -> None:\n    for sumaCadenas in [sumaCadenas1, sumaCadenas2, sumaCadenas3,\n                        sumaCadenas4]:\n        assert sumaCadenas(\"2\",   \"6\")  == \"8\"\n        assert sumaCadenas(\"14\",  \"2\")  == \"16\"\n        assert sumaCadenas(\"14\",  \"-5\") == \"9\"\n        assert sumaCadenas(\"-14\", \"-5\") == \"-19\"\n        assert sumaCadenas(\"5\",   \"-5\") == \"0\"\n        assert sumaCadenas(\"\",    \"5\")  == \"5\"\n        assert sumaCadenas(\"6\",   \"\")   == \"6\"\n        assert sumaCadenas(\"\",    \"\")   == \"0\"\n    print(\"Verificado\")\n\n# La verificaci\u00f3n es\n#    >>> test_sumaCadenas()\n#    Verificado\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Definir la funci\u00f3n sumaCadenas :: String -> String -> String tal que sumaCadenas xs ys es la cadena formada por el n\u00famero que es la suma de los n\u00fameros enteros cuyas cadenas que lo representan son xs e ys; adem\u00e1s, se supone que la cadena vac\u00eda representa al cero. Por ejemplo, sumaCadenas \u00ab2\u00bb \u00ab6\u00bb ==&#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":"default","_kad_post_title":"default","_kad_post_layout":"default","_kad_post_sidebar_id":"","_kad_post_content_style":"default","_kad_post_vertical_padding":"default","_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":[581],"tags":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/8488"}],"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=8488"}],"version-history":[{"count":2,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/8488\/revisions"}],"predecessor-version":[{"id":8498,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/8488\/revisions\/8498"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=8488"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=8488"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=8488"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}