{"id":1823,"date":"2023-07-24T20:30:21","date_gmt":"2023-07-24T20:30:21","guid":{"rendered":"https:\/\/statorials.org\/pt\/padronizar-dados-python\/"},"modified":"2023-07-24T20:30:21","modified_gmt":"2023-07-24T20:30:21","slug":"padronizar-dados-python","status":"publish","type":"post","link":"https:\/\/statorials.org\/pt\/padronizar-dados-python\/","title":{"rendered":"Como padronizar dados em python: com exemplos"},"content":{"rendered":"<p><\/p>\n<hr>\n<p><span style=\"color: #000000;\"><strong>Padronizar<\/strong> um conjunto de dados significa dimensionar todos os valores no conjunto de dados de forma que o valor m\u00e9dio seja 0 e o desvio padr\u00e3o seja 1.<\/span><\/p>\n<p> <span style=\"color: #000000;\">Usamos a seguinte f\u00f3rmula para normalizar valores em um conjunto de dados:<\/span><\/p>\n<p> <span style=\"color: #000000;\"><strong>x <sub>novo<\/sub> = (x <sub>i<\/sub> \u2013 <span style=\"text-decoration: overline;\">x<\/span> ) \/ s<\/strong><\/span><\/p>\n<p> <span style=\"color: #000000;\">Ouro:<\/span><\/p>\n<ul>\n<li> <span style=\"color: #000000;\"><strong>x <sub>i<\/sub><\/strong> : o i- <sup>\u00e9simo<\/sup> valor do conjunto de dados<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong><span style=\"text-decoration: overline;\">x<\/span><\/strong> : A amostra significa<\/span><\/li>\n<li> <span style=\"color: #000000;\"><strong>s<\/strong> : o desvio padr\u00e3o da amostra<\/span><\/li>\n<\/ul>\n<p> <span style=\"color: #000000;\">Podemos usar a seguinte sintaxe para normalizar rapidamente todas as colunas em um DataFrame do pandas em Python:<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <strong>(df- <span style=\"color: #3366ff;\">df.mean<\/span> ())\/df. <span style=\"color: #3366ff;\">std<\/span> ()\n<\/strong><\/pre>\n<p> <span style=\"color: #000000;\">Os exemplos a seguir mostram como usar essa sintaxe na pr\u00e1tica.<\/span><\/p>\n<h3> <span style=\"color: #000000;\"><strong>Exemplo 1: padronizar todas as colunas do DataFrame<\/strong><\/span><\/h3>\n<p> <span style=\"color: #000000;\">O c\u00f3digo a seguir mostra como padronizar todas as colunas em um DataFrame do pandas:<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <b><span style=\"color: #008000;\">import<\/span> pandas <span style=\"color: #008000;\">as<\/span> pd\n\n<span style=\"color: #008080;\">#create data frame\n<\/span>df = pd. <span style=\"color: #3366ff;\">DataFrame<\/span> ({' <span style=\"color: #ff0000;\">y<\/span> ': [8, 12, 15, 14, 19, 23, 25, 29],\n                   ' <span style=\"color: #ff0000;\">x1<\/span> ': [5, 7, 7, 9, 12, 9, 9, 4],\n                   ' <span style=\"color: #ff0000;\">x2<\/span> ': [11, 8, 10, 6, 6, 5, 9, 12],\n                   ' <span style=\"color: #ff0000;\">x3<\/span> ': [2, 2, 3, 2, 5, 5, 7, 9]})\n\n<span style=\"color: #008080;\">#view data frame\n<\/span>df\n\n\ty x1 x2 x3\n0 8 5 11 2\n1 12 7 8 2\n2 15 7 10 3\n3 14 9 6 2\n4 19 12 6 5\n5 23 9 5 5\n6 25 9 9 7\n7 29 4 12 9\n\n<span style=\"color: #008080;\">#standardize the values in each column\n<\/span>df_new = (df- <span style=\"color: #3366ff;\">df.mean<\/span> ())\/df. <span style=\"color: #3366ff;\">std<\/span> ()\n\n<span style=\"color: #008080;\">#view new data frame\n<\/span>df_new\n\n\t        y x1 x2 x3\n0 -1.418032 -1.078639 1.025393 -0.908151\n1 -0.857822 -0.294174 -0.146485 -0.908151\n2 -0.437664 -0.294174 0.634767 -0.525772\n3 -0.577717 0.490290 -0.927736 -0.908151\n4 0.122546 1.666987 -0.927736 0.238987\n5 0.682756 0.490290 -1.318362 0.238987\n6 0.962861 0.490290 0.244141 1.003746\n7 1.523071 -1.470871 1.416019 1.768505<\/b><\/pre>\n<p> <span style=\"color: #000000;\">Podemos verificar que a m\u00e9dia e o desvio padr\u00e3o de cada coluna s\u00e3o respectivamente iguais a 0 e 1:<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <b><span style=\"color: #008080;\">#view mean of each column\n<\/span>df_new. <span style=\"color: #3366ff;\">mean<\/span> ()\n\ny 0.000000e+00\nx1 2.775558e-17\nx2 -4.163336e-17\nx3 5.551115e-17\ndtype:float64\n\n<span style=\"color: #008080;\">#view standard deviation of each column\n<\/span>df_new. <span style=\"color: #3366ff;\">std<\/span> ()\n\ny 1.0\nx1 1.0\nx2 1.0\nx3 1.0\ndtype:float64\n<\/b><\/pre>\n<h3> <span style=\"color: #000000;\"><strong>Exemplo 2: Normalizar colunas espec\u00edficas do DataFrame<\/strong><\/span><\/h3>\n<p> <span style=\"color: #000000;\">\u00c0s vezes voc\u00ea pode querer normalizar apenas colunas espec\u00edficas em um DataFrame.<\/span><\/p>\n<p> <span style=\"color: #000000;\">Por exemplo, para muitos <a href=\"https:\/\/statorials.org\/pt\/estatologia-explica-conceitos-de-forma-simples-e-direta-facilitamos-o-aprendizado-de-estatistica\/\" target=\"_blank\" rel=\"noopener\">algoritmos de aprendizado de m\u00e1quina,<\/a> talvez voc\u00ea queira padronizar apenas as vari\u00e1veis preditoras antes de ajustar um determinado modelo aos dados.<\/span><\/p>\n<p> <span style=\"color: #000000;\">O c\u00f3digo a seguir mostra como padronizar colunas espec\u00edficas em um DataFrame do pandas:<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <b><span style=\"color: #008000;\">import<\/span> pandas <span style=\"color: #008000;\">as<\/span> pd\n\n<span style=\"color: #008080;\">#create data frame\n<\/span>df = pd. <span style=\"color: #3366ff;\">DataFrame<\/span> ({' <span style=\"color: #ff0000;\">y<\/span> ': [8, 12, 15, 14, 19, 23, 25, 29],\n                   ' <span style=\"color: #ff0000;\">x1<\/span> ': [5, 7, 7, 9, 12, 9, 9, 4],\n                   ' <span style=\"color: #ff0000;\">x2<\/span> ': [11, 8, 10, 6, 6, 5, 9, 12],\n                   ' <span style=\"color: #ff0000;\">x3<\/span> ': [2, 2, 3, 2, 5, 5, 7, 9]})\n\n<span style=\"color: #008080;\">#view data frame\n<\/span>df\n\n\ty x1 x2 x3\n0 8 5 11 2\n1 12 7 8 2\n2 15 7 10 3\n3 14 9 6 2\n4 19 12 6 5\n5 23 9 5 5\n6 25 9 9 7\n7 29 4 12 9\n\n<span style=\"color: #008080;\">#define predictor variable columns<\/span>\ndf_x = df[[' <span style=\"color: #ff0000;\">x1<\/span> ', ' <span style=\"color: #ff0000;\">x2<\/span> ', ' <span style=\"color: #ff0000;\">x3<\/span> ']]\n\n<span style=\"color: #008080;\">#standardize the values for each predictor variable\n<\/span>df[[' <span style=\"color: #ff0000;\">x1<\/span> ',' <span style=\"color: #ff0000;\">x2<\/span> ',' <span style=\"color: #ff0000;\">x3<\/span> ']] = (df_x- <span style=\"color: #3366ff;\">df_x.mean<\/span> ())\/df_x. <span style=\"color: #3366ff;\">std<\/span> ()\n\n<span style=\"color: #008080;\">#view new data frame\n<\/span>df\n\n         y x1 x2 x3\n0 8 -1.078639 1.025393 -0.908151\n1 12 -0.294174 -0.146485 -0.908151\n2 15 -0.294174 0.634767 -0.525772\n3 14 0.490290 -0.927736 -0.908151\n4 19 1.666987 -0.927736 0.238987\n5 23 0.490290 -1.318362 0.238987\n6 25 0.490290 0.244141 1.003746\n7 29 -1.470871 1.416019 1.768505<\/b><\/pre>\n<p> <span style=\"color: #000000;\">Observe que a coluna \u201cy\u201d permanece inalterada, mas as colunas \u201cx1\u201d, \u201cx2\u201d e \u201cx3\u201d s\u00e3o todas padronizadas.<\/span><\/p>\n<p> <span style=\"color: #000000;\">Podemos verificar que a m\u00e9dia e o desvio padr\u00e3o de cada coluna de vari\u00e1veis preditoras s\u00e3o iguais a 0 e 1, respectivamente:<\/span><\/p>\n<pre style=\"background-color: #ececec; font-size: 15px;\"> <b><span style=\"color: #008080;\">#view mean of each predictor variable column\n<\/span>df[[' <span style=\"color: #ff0000;\">x1<\/span> ', ' <span style=\"color: #ff0000;\">x2<\/span> ', ' <span style=\"color: #ff0000;\">x3<\/span> ']]. <span style=\"color: #3366ff;\">mean<\/span> ()\n\nx1 2.775558e-17\nx2 -4.163336e-17\nx3 5.551115e-17\ndtype:float64\n\n<span style=\"color: #008080;\">#view standard deviation of each predictor variable column\n<\/span>df[[' <span style=\"color: #ff0000;\">x1<\/span> ', ' <span style=\"color: #ff0000;\">x2<\/span> ', ' <span style=\"color: #ff0000;\">x3<\/span> ']]. <span style=\"color: #3366ff;\">std<\/span> ()\n\nx1 1.0\nx2 1.0\nx3 1.0\ndtype:float64<\/b><\/pre>\n<h3> <strong><span style=\"color: #000000;\">Recursos adicionais<\/span><\/strong><\/h3>\n<p> <a href=\"https:\/\/statorials.org\/pt\/normalizar-colunas-do-dataframe-do-pandas\/\" target=\"_blank\" rel=\"noopener\">Como normalizar colunas em um DataFrame do Pandas<\/a><br \/> <a href=\"https:\/\/statorials.org\/pt\/remover-valores-discrepantes-python\/\" target=\"_blank\" rel=\"noopener\">Como remover valores discrepantes em Python<\/a><br \/> <a href=\"https:\/\/statorials.org\/pt\/padronizacao-vs-normalizacao\/\" target=\"_blank\" rel=\"noopener\">Padroniza\u00e7\u00e3o ou normaliza\u00e7\u00e3o: qual a diferen\u00e7a?<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Padronizar um conjunto de dados significa dimensionar todos os valores no conjunto de dados de forma que o valor m\u00e9dio seja 0 e o desvio padr\u00e3o seja 1. Usamos a seguinte f\u00f3rmula para normalizar valores em um conjunto de dados: x novo = (x i \u2013 x ) \/ s Ouro: x i : o [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-1823","post","type-post","status-publish","format-standard","hentry","category-guia"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v21.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Como padronizar dados em Python: com exemplos<\/title>\n<meta name=\"description\" content=\"Este tutorial explica como padronizar dados em Python, com v\u00e1rios exemplos.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/statorials.org\/pt\/padronizar-dados-python\/\" \/>\n<meta property=\"og:locale\" content=\"pt_PT\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Como padronizar dados em Python: com exemplos\" \/>\n<meta property=\"og:description\" content=\"Este tutorial explica como padronizar dados em Python, com v\u00e1rios exemplos.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/statorials.org\/pt\/padronizar-dados-python\/\" \/>\n<meta property=\"og:site_name\" content=\"Statorials\" \/>\n<meta property=\"article:published_time\" content=\"2023-07-24T20:30:21+00:00\" \/>\n<meta name=\"author\" content=\"Dr. benjamim anderson\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Escrito por\" \/>\n\t<meta name=\"twitter:data1\" content=\"Dr. benjamim anderson\" \/>\n\t<meta name=\"twitter:label2\" content=\"Tempo estimado de leitura\" \/>\n\t<meta name=\"twitter:data2\" content=\"3 minutos\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/statorials.org\/pt\/padronizar-dados-python\/\",\"url\":\"https:\/\/statorials.org\/pt\/padronizar-dados-python\/\",\"name\":\"Como padronizar dados em Python: com exemplos\",\"isPartOf\":{\"@id\":\"https:\/\/statorials.org\/pt\/#website\"},\"datePublished\":\"2023-07-24T20:30:21+00:00\",\"dateModified\":\"2023-07-24T20:30:21+00:00\",\"author\":{\"@id\":\"https:\/\/statorials.org\/pt\/#\/schema\/person\/e08f98e8db95e0aa9c310e1b27c9c666\"},\"description\":\"Este tutorial explica como padronizar dados em Python, com v\u00e1rios exemplos.\",\"breadcrumb\":{\"@id\":\"https:\/\/statorials.org\/pt\/padronizar-dados-python\/#breadcrumb\"},\"inLanguage\":\"pt-PT\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/statorials.org\/pt\/padronizar-dados-python\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/statorials.org\/pt\/padronizar-dados-python\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Lar\",\"item\":\"https:\/\/statorials.org\/pt\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Como padronizar dados em python: com exemplos\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/statorials.org\/pt\/#website\",\"url\":\"https:\/\/statorials.org\/pt\/\",\"name\":\"Statorials\",\"description\":\"O seu guia para a literacia estat\u00edstica!\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/statorials.org\/pt\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"pt-PT\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/statorials.org\/pt\/#\/schema\/person\/e08f98e8db95e0aa9c310e1b27c9c666\",\"name\":\"Dr. benjamim anderson\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"pt-PT\",\"@id\":\"https:\/\/statorials.org\/pt\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/statorials.org\/pt\/wp-content\/uploads\/2023\/10\/Dr.-Benjamin-Anderson-96x96.jpg\",\"contentUrl\":\"https:\/\/statorials.org\/pt\/wp-content\/uploads\/2023\/10\/Dr.-Benjamin-Anderson-96x96.jpg\",\"caption\":\"Dr. benjamim anderson\"},\"description\":\"Ol\u00e1, sou Benjamin, um professor aposentado de estat\u00edstica que se tornou professor dedicado na Statorials. 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