{"id":379,"date":"2022-02-03T15:03:02","date_gmt":"2022-02-03T14:03:02","guid":{"rendered":"http:\/\/justmakeit.es\/?p=379"},"modified":"2022-02-03T15:03:02","modified_gmt":"2022-02-03T14:03:02","slug":"convertir-un-dataset-en-un-hashmap","status":"publish","type":"post","link":"http:\/\/justmakeit.es\/?p=379","title":{"rendered":"Convertir un Dataset<Row> en un HashMap"},"content":{"rendered":"\n<p>En ocasiones es necesario pasar a una funci\u00f3n de transformaci\u00f3n informaci\u00f3n en la que buscar datos necesarios para la transformaci\u00f3n y el resultado. <\/p>\n\n\n\n<p>En estos casos, se pueden pasar dichos datos como List o idealmente como HashMap si vas a conocer el valor de la clave por la que buscar, ya que as\u00ed ser\u00e1 mucho m\u00e1s r\u00e1pido. <\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>HashMap map2 = new HashMap&lt;>();\n\nDataset&lt;Row> ds = sparkSession.sql(select * from db.tableName);\nds.collectAsList().forEach((Row row) -> {\n\nString id = row.get(1).toString();\nif (map2.containsKey(id)) {\n\t((ArrayList) map2.get(id)).add(row);\n\t} else {\n\t\tList&lt;Row> ls = new ArrayList&lt;Row>();\n\t\tls.add(row);\n\t\tmap2.put(id, ls);\n\t}\n});<\/code><\/pre>\n\n\n\n<p>En este caso lo que se va a guardar dentro del HashMap es un listado de los Row que tienen el mismo Id<\/p>\n","protected":false},"excerpt":{"rendered":"<p>En ocasiones es necesario pasar a una funci\u00f3n de transformaci\u00f3n informaci\u00f3n en la que buscar datos necesarios para la transformaci\u00f3n &hellip; <a href=\"http:\/\/justmakeit.es\/?p=379\" class=\"btn btn-readmore\">Read More <span class=\"screen-reader-text\"> \u00abConvertir un Dataset<Row> en un HashMap\u00bb<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[49,36,34],"class_list":["post-379","post","type-post","status-publish","format-standard","hentry","category-cosos","tag-dataset","tag-java","tag-spark"],"_links":{"self":[{"href":"http:\/\/justmakeit.es\/index.php?rest_route=\/wp\/v2\/posts\/379","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/justmakeit.es\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/justmakeit.es\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/justmakeit.es\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/justmakeit.es\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=379"}],"version-history":[{"count":1,"href":"http:\/\/justmakeit.es\/index.php?rest_route=\/wp\/v2\/posts\/379\/revisions"}],"predecessor-version":[{"id":381,"href":"http:\/\/justmakeit.es\/index.php?rest_route=\/wp\/v2\/posts\/379\/revisions\/381"}],"wp:attachment":[{"href":"http:\/\/justmakeit.es\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=379"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/justmakeit.es\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=379"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/justmakeit.es\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=379"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}