{"id":2754,"date":"2023-07-20T20:46:38","date_gmt":"2023-07-20T20:46:38","guid":{"rendered":"https:\/\/statorials.org\/pt\/substring-mongodb\/"},"modified":"2023-07-20T20:46:38","modified_gmt":"2023-07-20T20:46:38","slug":"substring-mongodb","status":"publish","type":"post","link":"https:\/\/statorials.org\/pt\/substring-mongodb\/","title":{"rendered":"Mongodb: como usar a fun\u00e7\u00e3o $susbtr"},"content":{"rendered":"

<\/p>\n

\n

Voc\u00ea pode usar a fun\u00e7\u00e3o $substr<\/strong> no MongoDB para extrair uma substring de uma string.<\/span><\/p>\n

Esta fun\u00e7\u00e3o usa a seguinte sintaxe b\u00e1sica:<\/span><\/p>\n

 db.myCollection.aggregate([\n  { $project<\/span> : {substring: { $substr<\/span> : [ \" $fullstring<\/span> \", 0, 4 ] }}}\n])<\/strong><\/pre>\n
 Este exemplo espec\u00edfico extrai todos os quatro caracteres do campo denominado “fullString” come\u00e7ando na posi\u00e7\u00e3o 0.<\/span><\/p>\n
 O exemplo a seguir mostra como usar essa sintaxe na pr\u00e1tica com uma venda<\/span> de cobran\u00e7a com os seguintes documentos:<\/span><\/p>\n
 db.sales.insertOne({yearMonth: 201702, amount: 40<\/span> })\ndb.sales.insertOne({yearMonth: 201802, amount: 32<\/span> })\ndb.sales.insertOne({yearMonth: 201806, amount: 19<\/span> })\ndb.sales.insertOne({yearMonth: 201910, amount: 29<\/span> })\ndb.sales.insertOne({yearMonth: 201907, amount: 35<\/span> })<\/strong><\/pre>\n
 Exemplo: como usar a fun\u00e7\u00e3o $susbtr no MongoDB<\/strong><\/span><\/h3>\n
 Podemos usar o c\u00f3digo a seguir para extrair os primeiros quatro caracteres do campo \u201cyearMonth\u201d e exibi-los em um novo campo chamado \u201cyear\u201d:<\/span><\/p>\n
 db.sales.aggregate([\n  { $project<\/span> : {year: { $substr<\/span> : [ \" $yearMonth<\/span> \", 0, 4 ] }}}\n])\n<\/strong><\/pre>\n
 Este c\u00f3digo produz o seguinte resultado:<\/span><\/p>\n
 { _id: ObjectId(\"620145544cb04b772fd7a929\"), year: '2017' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92a\"), year: '2018' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92b\"), year: '2018' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92c\"), year: '2019' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92d\"), year: '2019' }<\/strong><\/pre>\n
 Observe que os primeiros quatro caracteres do campo \u201cm\u00easAno\u201d de cada documento s\u00e3o exibidos em um novo campo denominado \u201cano\u201d.<\/span><\/p>\n
 \u00c9 importante observar que este c\u00f3digo exibe<\/em> apenas a substring.<\/span><\/p>\n
 Para realmente adicionar um novo campo \u00e0 cole\u00e7\u00e3o que cont\u00e9m esta substring, precisamos usar a fun\u00e7\u00e3o $merge<\/strong> da seguinte forma:<\/span><\/p>\n
 db.sales.aggregate([\n  { $project<\/span> : {year: { $substr<\/span> : [ \" $yearMonth<\/span> \", 0, 4 ] }}},\n  { $merge<\/span> : \"sales\" }\n])<\/strong><\/pre>\n
 Esta \u00e9 a apar\u00eancia da cole\u00e7\u00e3o atualizada agora:<\/span><\/p>\n
 { _id: ObjectId(\"620145544cb04b772fd7a929\"),\n  yearMonth: 201702,\n  amount: 40,\n  year: '2017' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92a\"),\n  yearMonth: 201802,\n  amount: 32,\n  year: '2018' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92b\"),\n  yearMonth: 201806,\n  amount: 19,\n  year: '2018' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92c\"),\n  yearMonth: 201910,\n  amount: 29,\n  year: '2019' }\n{ _id: ObjectId(\"620145544cb04b772fd7a92d\"),\n  yearMonth: 201907,\n  amount: 35,\n  year: '2019' }<\/strong><\/pre>\n
 Observe que o novo campo intitulado \u201cano\u201d foi adicionado a cada documento da cole\u00e7\u00e3o e exibe os primeiros quatro caracteres do campo \u201canoM\u00eas\u201d.<\/span><\/p>\n
 Nota<\/strong> : Voc\u00ea pode encontrar a documenta\u00e7\u00e3o completa da fun\u00e7\u00e3o $substr<\/strong> aqui<\/a> .<\/span><\/p>\n
 Recursos adicionais<\/strong><\/span><\/h3>\n
 Os tutoriais a seguir explicam como realizar outras opera\u00e7\u00f5es comuns no MongoDB:<\/span><\/p>\n
 MongoDB: Como verificar se o campo cont\u00e9m uma string<\/a>
MongoDB: Como concatenar strings de dois campos<\/a>
 MongoDB: Como substituir strings<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
Voc\u00ea pode usar a fun\u00e7\u00e3o $substr no MongoDB para extrair uma substring de uma string. Esta fun\u00e7\u00e3o usa a seguinte sintaxe b\u00e1sica: db.myCollection.aggregate([ { $project : {substring: { $substr : [ ” $fullstring “, 0, 4 ] }}} ]) Este exemplo espec\u00edfico extrai todos os quatro caracteres do campo denominado “fullString” come\u00e7ando na posi\u00e7\u00e3o 0. […]<\/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-2754","post","type-post","status-publish","format-standard","hentry","category-guia"],"yoast_head":"\nMongoDB: Como usar a fun\u00e7\u00e3o $susbtr - Estatologia<\/title>\n<meta name=\"description\" content=\"Este tutorial explica como usar a fun\u00e7\u00e3o substr no MongoDB para extrair uma substring de uma string, com 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\/substring-mongodb\/\" \/>\n<meta property=\"og:locale\" content=\"pt_PT\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"MongoDB: Como usar a fun\u00e7\u00e3o $susbtr - Estatologia\" \/>\n<meta property=\"og:description\" content=\"Este tutorial explica como usar a fun\u00e7\u00e3o substr no MongoDB para extrair uma substring de uma string, com exemplos.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/statorials.org\/pt\/substring-mongodb\/\" \/>\n<meta property=\"og:site_name\" content=\"Statorials\" \/>\n<meta property=\"article:published_time\" content=\"2023-07-20T20:46:38+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=\"2 minutos\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/statorials.org\/pt\/substring-mongodb\/\",\"url\":\"https:\/\/statorials.org\/pt\/substring-mongodb\/\",\"name\":\"MongoDB: Como usar a fun\u00e7\u00e3o $susbtr - Estatologia\",\"isPartOf\":{\"@id\":\"https:\/\/statorials.org\/pt\/#website\"},\"datePublished\":\"2023-07-20T20:46:38+00:00\",\"dateModified\":\"2023-07-20T20:46:38+00:00\",\"author\":{\"@id\":\"https:\/\/statorials.org\/pt\/#\/schema\/person\/e08f98e8db95e0aa9c310e1b27c9c666\"},\"description\":\"Este tutorial explica como usar a fun\u00e7\u00e3o substr no MongoDB para extrair uma substring de uma string, com exemplos.\",\"breadcrumb\":{\"@id\":\"https:\/\/statorials.org\/pt\/substring-mongodb\/#breadcrumb\"},\"inLanguage\":\"pt-PT\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/statorials.org\/pt\/substring-mongodb\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/statorials.org\/pt\/substring-mongodb\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Lar\",\"item\":\"https:\/\/statorials.org\/pt\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Mongodb: como usar a fun\u00e7\u00e3o $susbtr\"}]},{\"@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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