{"id":7,"date":"2023-10-08T11:23:40","date_gmt":"2023-10-08T11:23:40","guid":{"rendered":"https:\/\/tutorialsexample.com\/?p=7"},"modified":"2023-10-08T12:18:42","modified_gmt":"2023-10-08T12:18:42","slug":"kotlin-scope-function","status":"publish","type":"post","link":"https:\/\/tutorialsexample.com\/index.php\/2023\/10\/08\/kotlin-scope-function\/","title":{"rendered":"Kotlin \u2013 Scope Function"},"content":{"rendered":"\t\t
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Kotlin: Scope Functions<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Scope functions are functions that execute a block of code within the context of an object.<\/p>\n

Scope functions provides a way to give temporary scope<\/strong> to the object, where specific operations can be applied<\/strong> to the object within the block of code.<\/p>\n

Scope functions make your code more concise and readable.<\/p>\n


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In Kotlin, scope functions are a set of functions that are used to perform operations on objects within a specific context, often referred to as the receiver object. These scope functions allow you to execute a block of code while providing a concise and expressive way to work with objects, set properties, or perform operations on them. They are particularly useful for reducing redundancy, improving code readability, and managing variable scopes.<\/p>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Example: Without using scope function

class KRDCompany() {
\u00a0\u00a0 \u00a0lateinit var name: String
\u00a0\u00a0 \u00a0lateinit var objective: String
\u00a0\u00a0 \u00a0lateinit var founder: String
}

fun main() {
\u00a0\u00a0 \u00a0\/\/ without using scope function

\u00a0\u00a0 \u00a0\/\/ creating instance of KRDCompany Class
\u00a0\u00a0 \u00a0val krd = KRDCompany()

\u00a0\u00a0 \u00a0\/\/ initializing members of the class
\u00a0\u00a0\u00a0 krd.name = “TutorialsExample”
\u00a0\u00a0\u00a0 krd.objective = “A tutorials portal”
\u00a0\u00a0\u00a0 krd.founder = “Rajnish “

\u00a0\u00a0 \u00a0println(krd.name)
}
<\/strong><\/p>

\u00a0<\/p>

Output:<\/strong><\/p>

TutorialsExample<\/pre>
  1. It’s apparent that, in the absence of scope functions, we are required to include the object name each time we wish to access class members. Conversely, when employing scope functions, direct reference to members can be made without the need for the object name. This represents one of the practical applications of scope functions, which we will explore further in this article.<\/p><\/li>
  2. You might have observed that, without the use of scope functions, repetitive object naming is essential for accessing class members. In contrast, scope functions enable us to access members directly, eliminating the need for object names. This constitutes one of the methods for leveraging scope functions, and we’ll delve deeper into their usage throughout this article.<\/p><\/li>
  3. It’s worth noting that, in the absence of scope functions, it’s obligatory to specify the object name whenever we want to access class members. Conversely, with the use of scope functions, we have the liberty to reference members directly, sans the object name. This is one of the practical applications of scope functions, and we’ll delve into them further in this article.<\/p><\/li><\/ol><\/div><\/div><\/div>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Types of scope functions<\/h3>
    There are five types of scope functions:<\/p>
    1. let<\/li>
    2. run<\/li>
    3. with<\/li>
    4. apply<\/li>
    5. also<\/li><\/ol>
      Differences in these functions:<\/strong><\/p>
      There are mainly two differences among these functions:<\/p>
      1. Way of referring to a context object<\/strong> (i.e. using either \u2018this\u2019 or \u2018it\u2019 keyword)<\/li>
      2. return value<\/strong> (i.e. returns either \u2018context object\u2019 or \u2018lambda result\u2019)<\/li><\/ol><\/div>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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        These scope functions provide different ways to work with objects, manage variable scopes, <\/p>\n\n\n\n\n\n\n\n\n\n
        Scope Function<\/th>\nPrimary Use Case<\/th>\nReturn Value<\/th>\n<\/tr>\n<\/thead>\n
        let<\/code><\/td>\nPerform operations on nullable objects and transform them.<\/td>\nResult of the lambda expression.<\/td>\n<\/tr>\n
        run<\/code><\/td>\nExecute code on non-nullable objects and access their properties\/methods.<\/td>\nResult of the lambda expression.<\/td>\n<\/tr>\n
        with<\/code><\/td>\nSimplify access to properties\/methods of an object (non-extension function).<\/td>\nResult of the lambda expression.<\/td>\n<\/tr>\n
        apply<\/code><\/td>\nInitialize or configure an object (non-extension function).<\/td>\nThe modified object itself.<\/td>\n<\/tr>\n
        also<\/code><\/td>\nPerform side effects or logging on an object (non-extension function).<\/td>\nThe original object itself.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>

        <\/div>
        \n
        \n\n\n\n\n\n\n\n\n\n
        \n
        Function<\/p>\n<\/th>\n
        		\n
        Object Reference<\/p>\n<\/th>\n
        		\n
        Return Value<\/p>\n<\/th>\n<\/tr>\n<\/thead>\n
        \n
        let<\/p>\n<\/th>\n
        		\n
        it<\/p>\n<\/td>\n
        		\n
        Lambda result<\/p>\n<\/td>\n<\/tr>\n
        \n
        run<\/p>\n<\/th>\n
        		\n
        this<\/p>\n<\/td>\n
        		\n
        Lambda result<\/p>\n<\/td>\n<\/tr>\n
        \n
        with<\/p>\n<\/th>\n
        		\n
        this<\/p>\n<\/td>\n
        		\n
        Lambda result<\/p>\n<\/td>\n<\/tr>\n
        \n
        apply<\/p>\n<\/th>\n
        		\n
        this<\/p>\n<\/td>\n
        		\n
        Context object<\/p>\n<\/td>\n<\/tr>\n
        \n
        also<\/p>\n<\/th>\n
        		\n
        it<\/p>\n<\/td>\n
        		\n
        Context object<\/p><\/td><\/tr><\/tbody><\/table><\/figure><\/div>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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        1. let function

        <\/h3>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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        let function is often used to provide null safety calls. Use safe call operator(?.) with \u2018let\u2019 for null safety. It executes the block only with the non-null value.<\/span><\/h6>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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        fun main() {
        \u00a0\u00a0\u00a0 \/\/ Declare a nullable variable ‘number’ with an initial value of null.
        \u00a0\u00a0\u00a0 var number: Int? = null

        \u00a0\u00a0\u00a0 \/\/ Use the ‘let’ function to perform operations when ‘number’ is not null.
        \u00a0\u00a0\u00a0 number?.let {
        \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ These statements will not execute because ‘number’ is null.
        \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print(it)
        \u00a0\u00a0\u00a0 }

        \u00a0\u00a0\u00a0 \/\/ Re-initialize the value of ‘number’ to 2.
        \u00a0\u00a0\u00a0 number = 2

        \u00a0\u00a0\u00a0 \/\/ Use the ‘let’ function again to perform operations when ‘number’ is not null.
        \u00a0\u00a0\u00a0 number?.let {
        \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ These statements will execute because ‘number’ is not null.
        \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 print(number)
        \u00a0\u00a0\u00a0 }
        }

        <\/p>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"
        Kotlin: Scope Functions Scope functions are functions that execute a block of code within the context of an object. Scope functions provides a way to give temporary scope to the object, where specific operations can be applied to the object within the block of code. Scope functions make your code more concise and readable. In …<\/p>\n
          Kotlin \u2013 Scope Function<\/span> Read More »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","footnotes":""},"categories":[7],"tags":[10,11,9,8],"_links":{"self":[{"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/posts\/7"}],"collection":[{"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/comments?post=7"}],"version-history":[{"count":4,"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/posts\/7\/revisions"}],"predecessor-version":[{"id":13,"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/posts\/7\/revisions\/13"}],"wp:attachment":[{"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/media?parent=7"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/categories?post=7"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tutorialsexample.com\/index.php\/wp-json\/wp\/v2\/tags?post=7"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}