{"id":2317,"date":"2020-06-20T21:01:04","date_gmt":"2020-06-20T15:31:04","guid":{"rendered":"https:\/\/golangbyexamples.com\/?p=2317"},"modified":"2021-04-06T18:10:40","modified_gmt":"2021-04-06T12:40:40","slug":"length-of-string-golang","status":"publish","type":"post","link":"https:\/\/golangbyexamples.com\/length-of-string-golang\/","title":{"rendered":"Length of string in Go (Golang)"},"content":{"rendered":"\n<p class=\"has-medium-font-size\">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.&nbsp;All other characters are between 1 -4 bytes. To understand it more consider the below string<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">sample := \"a\u00a3c\"<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">In above string<\/p>\n\n\n\n<ul class=\"has-medium-font-size wp-block-list\"><li>&#8216;a&#8217; takes one byte as per UTF-8<\/li><li>&#8216;\u00a3&#8217; takes two bytes as per UTF-8<\/li><li>&#8216;b&#8217; takes one byte as per UTF-8<\/li><\/ul>\n\n\n\n<p class=\"has-medium-font-size\">The above string has 1+2+1 = 4 bytes altogether. Therefore when we try to print the length of the string using the standard <strong>len()<\/strong> function it will output 4 and not 3 as <strong>len()<\/strong> function returns the number of bytes in the string.<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">fmt.Printf(\"Length is %d\\n\", len(sample))<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">Hence standalone for loop cannot be used to iterate over all characters of a string as it will iterate over bytes and not character. So below <strong>for<\/strong> loop will instead iterate four times and the print value corresponding to a byte at that index.<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">for i := 0; i < len(sample); i++ {\n    fmt.Printf(\"%c\\n\", sample[i])\n }<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">It will output below string which is not same as <strong>sample <\/strong>string<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">a\u00c2\u00a3b<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">Not we have mentioned the above limitation of using len() function and for loop, let's see two ways of calculating the length of the string.<\/p>\n\n\n\n<ul class=\"has-medium-font-size wp-block-list\"><li>Using the <strong>RuneCountInString<\/strong> method of the utf8 package<\/li><li>Using for-range loop<\/li><li>By converting string to a rune array.<\/li><\/ul>\n\n\n\n<p class=\"has-large-font-size\"><strong>Using the <strong>RuneCountInString<\/strong> method of the utf8 package<\/strong><\/p>\n\n\n\n<p class=\"has-medium-font-size\"><strong>utf8<\/strong> package of golang provides a RuneCountInString method that can be used to get the length of the string. It correctly counts the number of runes in the string.<\/p>\n\n\n\n<p class=\"has-medium-font-size\"><a href=\"https:\/\/golang.org\/pkg\/unicode\/utf8\/#RuneCountInString \">https:\/\/golang.org\/pkg\/unicode\/utf8\/#RuneCountInString<\/a><\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">package main\n\nimport (\n\t\"fmt\"\n\t\"unicode\/utf8\"\n)\n\nfunc main() {\n\tsample := \"a\u00a3b\"\n\n\tfmt.Printf(\"Length of given string is %d\\n\", utf8.RuneCountInString(sample))\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\">Length of given string is 3<\/code><\/pre>\n\n\n\n<p class=\"has-large-font-size\"><strong>Using for-range loop<\/strong><\/p>\n\n\n\n<p class=\"has-medium-font-size\">for-range iterates over the Unicode points( also referred to as rune in golang) in a string and will correctly output&nbsp; a, \u00a3, b. Hence it can also be used to calculate the length of the string. Here is the format when using for-range with string<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">for index, character := range string {\n    \/\/Do something with index and character\n}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\">Sample code<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">package main\n\nimport \"fmt\"\n\nfunc main() {\n\tsample := \"a\u00a3b\"\n\n\tlen := 0\n\t\/\/With index and value\n\tfmt.Println(\"Both Index and Value\")\n\tfor i, letter := range sample {\n\t\tlen++\n\t\tfmt.Printf(\"Start Index: %d Value:%s\\n\", i, string(letter))\n\t}\n\n\tfmt.Printf(\"Length of given string is %d\\n\", len)\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\">Start Index: 0 Value:a\nStart Index: 1 Value:\u00a3\nStart Index: 3 Value:b\nLength of given string is 3<\/code><\/pre>\n\n\n\n<p class=\"has-large-font-size\"><strong>By converting string to rune array<\/strong><\/p>\n\n\n\n<p class=\"has-medium-font-size\">A rune represents a Unicode Point. By converting a string to rune array basically it is same as creating a array of Unicode Points of that string. Therefore once the string is converted into the rune array, it can be used to iterate over all characters of the string.<\/p>\n\n\n\n<pre class=\"wp-block-prismatic-blocks\"><code class=\"language-go\">package main\n\nimport \"fmt\"\n\nfunc main() {\n\tsample := \"a\u00a3b\"\n\n\truneSample := []rune(sample)\n\n\tfmt.Printf(\"Length of given string is %d\\n\", len(runeSample))\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\">Length of given string is 3<\/code><\/pre>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>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.&nbsp;All other&#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":[3,4,294,149],"class_list":["post-2317","post","type-post","status-publish","format-standard","hentry","category-tech","tag-go","tag-golang","tag-length","tag-string"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.7 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Length of 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\/length-of-string-golang\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Length of string in Go (Golang) - Welcome To Golang By Example\" \/>\n<meta property=\"og:description\" content=\"In Golang string is a sequence of bytes. 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