{"id":1918,"date":"2020-03-31T15:59:17","date_gmt":"2020-03-31T15:59:17","guid":{"rendered":"https:\/\/golangbyexamples.com\/?p=1918"},"modified":"2020-03-31T15:59:28","modified_gmt":"2020-03-31T15:59:28","slug":"pick-random-character-string-golang","status":"publish","type":"post","link":"https:\/\/golangbyexamples.com\/pick-random-character-string-golang\/","title":{"rendered":"Pick a random character in string in Go (Golang)"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_17 counter-hierarchy counter-decimal ez-toc-light-blue\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" style=\"display: none;\"><i class=\"ez-toc-glyphicon ez-toc-icon-toggle\"><\/i><\/a><\/span><\/div>\n<nav><ul class=\"ez-toc-list ez-toc-list-level-1\"><li class=\"ez-toc-page-1 ez-toc-heading-level-1\"><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/golangbyexamples.com\/pick-random-character-string-golang\/#Overview\" title=\"Overview\">Overview<\/a><\/li><li class=\"ez-toc-page-1 ez-toc-heading-level-1\"><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/golangbyexamples.com\/pick-random-character-string-golang\/#Code\" title=\"Code\">Code<\/a><\/li><\/ul><\/nav><\/div>\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Overview\"><\/span><strong>Overview<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<p class=\"has-medium-font-size\"><strong>&#8216;mat\/rand&#8217; <\/strong>package of golang contains a <strong>Intn<\/strong> function that can be used to generate a pseudo-random number between [0,n). Bracket at the end means that n is exclusive. This function can be utilized to pick a random element in a string. We can generate a random between 0 and length-1 of string. Then we can use that random number to index into the string and get the result.<\/p>\n\n\n\n<p class=\"has-medium-font-size\">But there is one problem in above approach. In Golang string is a sequence of bytes. A string literal actually represents a UTF-8 sequence of bytes. In UTF-8, ASCII characters are single-byte corresponding to the first 128 Unicode characters.\u00a0All other characters are between 1 -4 bytes. Due to this it is not possible to index a character in a string.\u00a0 In GO, rune data type represents a Unicode point.\u00a0 Once a string is converted to an array of rune then it is possible to index a character in that array of rune. <\/p>\n\n\n\n<p class=\"has-medium-font-size\">You can learn more the above issue here &#8211; <a href=\"https:\/\/golangbyexamples.com\/number-characters-string-golang\/\">https:\/\/golangbyexamples.com\/number-characters-string-golang\/<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size\">For this reason in below program for picking a random in a given string , we\u00a0 are first converting a string into a rune array so that we can index into the rune array and then return the random character.<\/p>\n\n\n\n<h1 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Code\"><\/span><strong>Code<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">package main\n\nimport (\n    \"fmt\"\n    \"math\/rand\"\n)\n\nfunc main() {\n    in := \"abcdedf\u00a3\"\n    inRune := []rune(in)\n    randomIndex := rand.Intn(len(inRune))\n    pick := inRune[randomIndex]\n    fmt.Println(string(pick))\n}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\"><strong>Output:<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">One of a,b,c,d,e,f,\u00a3<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Table of Contents OverviewCode Overview &#8216;mat\/rand&#8217; package of golang contains a Intn function that can be used to generate a pseudo-random number between [0,n). Bracket at the end means that n is&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","footnotes":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false},"categories":[1],"tags":[144,3,4,260,248,149],"class_list":["post-1918","post","type-post","status-publish","format-standard","hentry","category-tech","tag-character","tag-go","tag-golang","tag-pick","tag-random","tag-string"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.7 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Pick a random character in string in Go (Golang) - Welcome To Golang By Example<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/golangbyexamples.com\/pick-random-character-string-golang\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Pick a random character in string in Go (Golang) - Welcome To Golang By Example\" \/>\n<meta property=\"og:description\" content=\"Table of Contents OverviewCode Overview &#8216;mat\/rand&#8217; package of golang contains a Intn function that can be used to generate a pseudo-random number between [0,n). 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