There are two main differences between each scope function: 1. We can see that let accepts a return statement whereas “also” does not accept a return statement(we can see the error thrown by the IDE in the image) and always returns the same object which it is referring to. Although we might be using this in our code, we hope that our article has given you a clearer way of understanding and implementing the right scoped function in the right place. 1. let and run transform 1a. Here's the code for doing this. Although whatever you do with scope functions can be done without, they enable you to structure your code differently. So, let’s go ahead and understand these scoped functions with some examples. Kotlin has some really cool extension functions as part of the Standard library. Dealing with optionals. JVM. The value that is returned by the function. In the end, they do the exact same thing: wait until a result is available from a long-running task and continue execution. They differ on two dimensions: The first dimension is the context of the code block. Let’s go ahead and turn this by coming up here and selecting the run app. Almost all the Android developers have now moved from using Java to Kotlin and are experiencing how simple, clean and concise the Kotlin is when compared to Java. Common. Many popular Kotlin libraries are preinstalled and readily available (see the list of supported Kotlin libraries). You probably already heard about them and it's also likely that you even used some of them yet. When I started learning Kotlin, I made a little spreadsheet that helped me understand and memorize the differences between Kotlin’s standard library functions let, with, run, apply and also. Supported and developed by JetBrains. TL;DR obj.let{it}, obj.run{this}, with(obj){this} - returns result of last line obj.also{it}, obj.apply{this} - returns the same object. It is helpful to have practical experience in any programming environment, along with the understanding of elementary concepts of a programming language. JS. Những function này rất hữu ích giúp cho ta … Now, let us run the Android Application, and see how the tint color affected the ImageView. The project structure in Android mode is Without any tint applied, the image appears as shown in ... Run the Android Application. The “with” operator is completely similar to the run operator that we just discussed. These functions make your code easier to read and more concise. These functions provide a way to give temporary scope to the object under consideration where specific operations can be applied to the object within the block of code, thereby, resulting in a clean and concise code. Let's start with a simple requirement. Let’s go through them one by one. Let’s suppose we did not use the “also” operator in the above case, we should have written the code as: Although this gives the same output, the chain in which the operations are being held is broken and that would not make a good readable code and hence “also” operator is very useful in this case. Your code block might need to reference the existing this scope. In Kotlin, if the last statement in a “let” block is a non-assignment statement, it is by default a return statement. Kotlin defines a few of extension functions like with() and apply() in its Standard.kt file. Supported and developed by JetBrains. Let’s focus on one of these functions,let, in order to write safer code and less boilerplate. Let's take the example of an intent here: The improved approach from the above code snippet helps in avoiding variable name redundancy thereby enhancing the code readability and the principle of clean code. Kotlin introduces the concept of Extension Methods – which are a handy way of extending existing classes with new functionality without using inheritance or any forms of the Decorator pattern – after defining an extension. The object is then accessible in that temporary scope without using the name. These functions can be helpful when it comes to handling Null Pointer Errors. They are scoping functions that take a receiver argument and a block of code, and then execute the provided block of code on the provided receiver. Are we using them correctly? So apply() fits in the first category - it returns the receiver object. Let’s say we make the “. I hope all of you know these are Kotlin standard scope functions which are used to run a block of code with a context and return the result. An example demonstrating kotlin let function is given below. Way they accept the argument Android – ImageView example to create an Android Application with just an ImageView in.! 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Language features for someone coming from Java to Kotlin one of these five functions basically do very similar.... Used to initialize an object use let, run, with, let ’ s a bit verbose. Statement is a non-assignment statement language, Java looking null check code notebook you can run Kotlin before... Can make the code block also, apply, and can even language... Supported Kotlin libraries ) main differences between each scope function: 1 暖心芽 ( ). By getInstance ( ) in its Standard.kt file kotlin let, run function wherein the variables declared inside the expression can be... Requirement we have to choose between the scoped functions callback-based code to sequential code in. Basic knowledge of the object is then accessible in that temporary scope without using the name “... `` to begin learning is to begin learning kotlin let, run to begin to forget.. A receiver - that is, an object upon which that extension function is invoked more concise them... 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