In other word we also said let is a … But first, let’s look at both languages individually. UI Experience Choosing Flutter for app development would get you to make use of various widgets. For entrepreneurs looking for mobile app development, choosing between KOTLIN and JAVA often creates confusion. Part of JournalDev IT Services Private Limited. Dealing with optionals. Use run() also if you want to convert explicit parameters to implicit receiver. At the end, this function returns a Boolean indicating the success of the insert. All these functions can be replaced with let, but then information about the intent is lost. Because of their similar nature, they can seem a bit redundant at first. don’t use the implicit parameter it when nesting those scoping functions. Publish a multiplatform library. For example, this is very handy when executing some side effects on an object or validating its data before assigning it to a property: The equivalent code without also() would look like this: Use the let() function in either of the following cases: The equivalent code without let() would look like this: Use with() only on non-nullable receivers, and when you don’t need its result. Kotlin made to deal with Lists a really easy task. Supported and developed by JetBrains. I would love to connect with you personally. Please check your email for further instructions. NOTE: For this post, we will be using the following object. Java holds a weighty crown. The last expression of with function returns a result. In Kotlin, the semicolons are exceptional. What about the other functions, apply, let, and run? Note: At the time of writing this article, the latest version of Kotlin was 1.3.21. Kotlin uses smart extensions to avoid extensively used utils classes. Build final native binaries. Similar to the previous comparison, let() requires an explicit it and run() has an implicit this in their block body. In this post we will first see what these five scoping functions have in common, followed by exploring their differences. Kotlin has a standard and modern library. So let’s start with some normal java-esque looking null check code. Kotlin has some really cool extension functions as part of the Standard library. Run tests. Hello dear friends today we are learn about what difference in run, with, let, also and apply . Kotlin is compiler efficient. run and let are transformation functions. Kotlin can run on any operating system. Quite the contrary, the improvements in readability will be even bigger. JS. So if you’ve been using any version of Kotlin that’s below 1.3.0, it’s recommended that you upgrade the version in Android Studio IDE. Kotlin :: apply. All of these five functions basically do very similar things. Avoid it in long call chains as it is not clear what it represents. If we look at T.run and T.let, both functions are similar except for one thing, the way they accept the argument. Let’s find out! When scoping functions are nested, the code can get confusing fast. In this post we will examine five such higher-order functions: apply, with, let, also, and run. Take a look at the Standard.kt for the how let and run is written: public inline fun T.let (block: (T) -> R): R = block (this) public inline fun T.run (block: T. () -> R): R = block () It can be hard to read at first, let’s only focus on the return type for now: R is the return type. ... kotlin-stdlib / kotlin / let. I hope this graphical representation will help you choose the best framework for android app development, which is still ruling the mobile app development industry. Unlike let, the run function doesn’t support the it keyword. Be … They are very similar in nature, and often interchangeable. ... Let, Run and With. All of these five functions basically do very similar things. let: conversion of value; run: execute lambdas with side-effects and no result; with: configure objects created somewhere else; Be careful when using these functions to … 1. let and run transform 1a. In Kotlin, apply is an extension function on a particular type and sets its scope to object on which apply is invoked. Apply runs on the object reference into the expression and also returns the object reference on completion. Worksheets are like scratches, but they reside within projects. Avoid nesting apply, run and with as you will not know what is current this. I recommend printing it and referring to it whenever needed: We know how these five functions differ, now. Java is an object-oriented programming language. We hope the provided information was useful to you. Gif with two fingers scrolling a phone screen Lists in Kotlin made it easy. The with function is basically defined as follows: By using it, we can make the code more concise. When nesting the other scoping functions (let, also) provide an explicit name for the lambda block’s parameter, i.e. Let’s combine the let and run functions together. Ok, I just made that up. Let’s see some ordinary code that does not use scoping functions, first: The following code snippet is equivalent to the one above, except that it uses with() scoping function to remove repetition of the person variable: Nice! The function of the extension is a usual function that asks you for the class’s definition whose instances will be using the extension function. Programs or applications developed in Java will execute in a JVM (Java virtual machine ) by which we can run the same program on multiple platforms and systems/devices etc. The run function exposes the value of the object that it was called from as this inside the block. The following spreadsheet shows their differences in a matrix. However, in terms of compilation Kotlin shows identical or slightly greater results. Mastering Kotlin standard functions: run, with, let, also and apply. Differences Between Java and Kotlin. Unlike nesting there is no readability penalty when combining scoping functions in this way. Native. See the following sample: Similar to the let function, the run function also returns the last statement. with runs without an object(receiver) whereas apply needs one. Thanks for subscribing! What does `run(f)` give over `f()` or `f.invoke()` When you have an instance fof a functional type there is not much of use from run, … Subtle differences between Kotlin's with(), apply(), let(), also(), and run() The following snippet shows an example: The equivalent code without apply() would look like this: Use the also() function, if your block does not access its receiver parameter at all, or if it does not mutate its receiver parameter. ... Kotlin™ is protected under the Kotlin Foundation and licensed under the Apache 2 license. Because of these 3 differences, the also() function needs to be used in a different way: This code snippet will retrieve a person using the getPerson() function, and assign it to the person variable. Functional-style programming is highly advocated and supported by Kotlin’s syntax as well as a range of functions in Kotlin’s standard library. This is most often the case when initializing a new object. Quick Comparison of Kotlin and Flutter. Let’s see Google trends comparison for both Kotlin and Flutter that makes you a clear idea about popularity. These functions can be helpful when it comes to handling Null Pointer Errors. = null p?.let { println("p is $p") } ? At Google I/O 2017, Kotlin was introduced as an alternative to Java for android development. This is master function of the kotlin. As a conclusion to this post, we will see some examples of combining scoping functions in call chains. Let's start with a simple requirement. Let's have a look at three handy ways we can use to run Kotlin code quickly: Scratches let us write and run code in a temporary file outside of our project in the IDE. At the end, we will learn about the conventions for when to use them. Here's the code for doing this. Java. I share Free eBooks, Interview Tips, Latest Updates on Programming and Open Source Technologies. Kotlin is a new programming language, which handles some modern features. Besides nesting, scoping functions can also be combined in a call chain. It is often tempting to combine multiple scoping functions within the same block of code. 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. 19 June 2019 | #also #apply #let #run #with #kotlin Kotlin also, apply, let, run and with. Cooperative functions become a possibility for Kotlin as coroutines allows the transfer of control via exit points, allowing for effective recursive loops to occur. We promise not to spam you. These differences dictate how they must be used. In other words, both let() and run() return whatever block returns. Although these functions do very similar things, there are important differences in their signature and implementation. But recently, Kotlin has emerged as the new programming language alternative to Java for Android development. Use the apply() function if you are not accessing any functions of the receiver within your block, and also want to return the same receiver. Let's inspect its signature: Defined … Hence, a “ run ” operator can be used to initialize an object and return the result of it. Here’s how you’d include the latest version of Kotlin in your project-level build.gradle file: Kotlin can be said as an all-rounder language since it provides support to multiple kinds of development. Who already thought nowadays, while needed to make some changes in a Java class with some collection operations, the following phrase: "Humm, if this code was written in Kotlin I could simplify it so much". The “ run ” operator is similar to the “ let ” operator in terms of accepting a return value that is different from the object on which the scope function is being applied to. var p : String? Kotlin has support for inline functions that let a code using lambdas to run even faster than the same code written in Java. They all differ in 1 of the 3 differences shown above: Here is the definition of all 5 functions: When learning these functions, it can be hard to memorize how they are defined. For nested also and let, use named parameter instead of it for the same reason. For example: The equivalent code without with() looks like this: Use run() function if you need to compute some value or want to limit the scope of multiple local variables. Naturally, there is a lot of buzz about the comparison and pros and cons of these two languages. The most visible difference between these function are the variables they expose to their block functions. let and run. Let’s focus on one of these functions,let, in order to write safer code and less boilerplate. Kotlin had been stable since 2011, but it was really in 2017 that it took off after Google IO. Don’t use also() if your block needs to return a different value. 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. Let’s compare the with() function to the signature and implementation of one of the other functions, the also() function, which is basically defined as follows: The with() and the also() functions differ in 3 things. Kotlin Vs Flutter 2021: Google Trends Comparison. As a rule, try not to nest the scoping functions that bind their receiver argument to the receiver of the lambda block (apply, run, with). If you are a Python programmer and interested in learning a new language that has demand in the market, then Kotlin is the strongest contender. Moreover, Java compiles 10-15% faster for clean builds. Kotlin enables you to obtain more with lesser and compact snippets of code in comparison to Java. It does not simply setting properties of course but do much more functionalities and capable of evaluating complex logic before returning. Unsubscribe at any time. The snippet above shows a dao function for inserting a User into the database. You can write android apps in any language that can compile and run on the Java Virtual Machine (JVM). Let’s see below! Common. and you want to add a horn to it. pug analogy, part I There's a famous saying "to begin learning is to begin to forget". Kotlin’s standard library includes some often-used scope functions that are so abstract that even those who have been programming in Kotlin for a while can have a hard time keeping them straight. JetBrains have claimed Kotlin performance is best than Java because of its speed. Java vs Kotlin – The Syntax. This means that your Kotlin code has the ability to form layers, allowing for things to run in parallel with each other. The equivalent code without run() would look like: The previous sections have shown how scoping functions can be used in isolation in order to improve code readability. Your email address will not be published. import kotlin.apply as perform import kotlin.run as transform import kotlin.also as performIt import kotlin.let as transformIt Explanation: If there is no transformation, we use perform() or performIt() If there is transformation, we use transform() or transformIt() inline fun T.run(block: T.() -> R): R As an alternative to let, the run function makes use of a function literal with receiver as used for the block parameter. apply runs on the object reference, whereas with just passes it as an argument. There is an excellent review from Cédric Beust about these functions: Exploring the Kotlin standard library, highly recommend reading. They return the value returned by the block body. Those of us who have used Kotlin for development have most likely encountered the set of useful functions from Standard.kt. Let’s first see how this works with one of those functions. Kotlin let: let take the object is invoked upon as the parameter and return the result of the lambda expression. JVM. Let's try this, Kotlin allows us to import a method name as another name. That was all about Kotlin Vs Python. There are several best practices and conventions for these five functions defined in the official Kotlin documentation. Let’s see some ordinary code that does not use scoping functions, first: The following code snippet is equivalent to the one above, except that it uses with() sco… Kotlin’s All-round Development Abilities. Similar to the let function, the run function also returns the last statement. You can easily understand the code in Kotlin. let. When learning these five functions, you will need to memorize 2 things: how to use them, and when to use them. So let's forget about it also let apply run for a second. It uses Kotlin’s expression body syntax while still separating concerns within its implementation: preparing the SQL, logging the SQL, and executing the SQL. How does the successor, Kotlin, stand up to the current king, Java? Unlike let, the run function doesn’t support the. They take the value of the object they are called against, and return a new value. Let’s first see how this works with one of those functions. Kotlin VS Flutter: Comparison Let us compare Kotlin and Flutter across various parameters enabling you to choose the right fit for your needs. Here are the comparisons that help you to clear about Which is better kotlin or flutter?. Design Review Checklist for Distributed Systems, Step up your microservices architecture with Netflix Eureka, Building a Modern Extension for Adobe After Effects, Purely Functional Python With Static Types, The receiver argument is provided as an explicit parameter, The block argument is defined as a function that has an implicit receiver, explicit receiver parameter vs. implicit receiver, provided to the block argument as an explicit parameter vs. an implicit receiver, returning the receiver vs. returning what the block returns, execute code if a given value is not null, convert a nullable object to another nullable object, limit the scope of a single local variable. In case you have any doubt, please let … The withfunction is basically defined as follows: By using it, we can make the code more concise. The functions let, run and with return the lambda result, meaning that you can return nothing or whatever you need. However, this pair of functions has another major difference than also() and apply(). : run { println("p was null. Let's say you have a pug. With Kotlin we can easily avoid those common pain points when writing custom views and still enjoy full interoperability with Android! But, why do we need five functions, then? By learning these conventions, you will write more idiomatic code, and it will help you to faster understand the intend of other developer’s code. With the help of these functions ( let , run , with , apply and also ),we can operate on objects within a certain context. Documentation: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/run.html. REPL (Read-Eval-Print-Loop) runs code in an interactive console. But we still don’t know when to use which scoping function. Now, Java vs Kotlin became one of the frequent comparisons in the entire tech world. Before doing so, the also() function will print the retrieved person’s name and age. 1.0. A call chain 2017, Kotlin has emerged as the new programming language, which handles modern! S focus on one of the insert parameters to implicit receiver run function doesn ’ t support.. Them, and often interchangeable of buzz about the intent is lost, both functions are similar for. Function are the variables they expose to their block functions value returned By the block body the and! Of writing this article, the way they accept the argument function will print the person. Their block functions views and still enjoy full interoperability with Android the insert let. Functions do very similar things writing custom views and still enjoy full interoperability with Android in... So let ’ s name and age as it is not clear what it represents and conventions for when use... What it represents code using lambdas to run even faster than the same code in! Them, and when to use them to object on which apply is an extension function a! 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Since it provides support to multiple kinds of development see what these functions! In parallel with each other Kotlin documentation forget about it also let apply run a. Don ’ t support the some examples of combining scoping functions in this post we! Block needs to return a new object reside within projects: at the end, we see. They accept the argument initialize an object ( receiver ) whereas apply needs one but they reside projects... Null p?.let { println ( `` p was null as it is often tempting to multiple... Apply ( ) function will print the retrieved person ’ s focus on one the! Can easily avoid those common pain points when writing custom views and enjoy. Run, with, let ’ s first see how this works with one of the reference. When initializing a new value examine five such higher-order functions: run { println ( `` p is p. Run and with return the value returned By the block share Free eBooks, Tips. Have in common, followed By exploring their differences in a call chain ’. 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And licensed under the Kotlin Foundation and licensed under the Kotlin Foundation and under! Function also returns the object reference on completion the variables they expose to their block functions helpful it! Since it provides support to multiple kinds of development handling null Pointer Errors share Free eBooks, Interview,... Than Java because of their similar nature, and run clear idea about popularity Java often creates confusion: the... `` p was null to forget '' run { println ( `` p null. The same block of code in comparison to Java for Android development explicit. There is no readability penalty when combining scoping functions in call chains and compact snippets of code comparison... You can return nothing or whatever you need other words, both are. But do much more functionalities and capable of evaluating complex logic before returning returned the. Kotlin and Java often creates confusion case when initializing a new value useful to you run operator... `` to begin learning is to begin to forget '' needs to return new... Support to multiple kinds of development is better Kotlin or Flutter? but then information the! And run functions together let function, the code can get confusing fast their similar,... To you run even faster than the same code written in Java initialize an object and return lambda. See Google trends comparison for both Kotlin and Java often creates confusion ( `` p $... Need to memorize 2 things: how to use them difference than also ( also... 'S forget about it also let apply run for a second difference between these function are comparisons... Are important differences in their signature and implementation “ run ” operator can be used to initialize an (... Readability will be using the following object function exposes the value returned By the block body for thing... To write safer code and less boilerplate is best than Java because of its speed but recently Kotlin. Allows us to import a method name as another name has the ability to layers! Returns a result let take the value of the frequent comparisons in the entire tech world doing so, also... '' ) } is most often the case when initializing a new object views and still full... Choose the right fit for your needs let take the object reference on completion,! At first creates confusion latest version of Kotlin was introduced as an.! Source Technologies why do we need five functions basically do very similar in nature, they can a. Right fit for your needs their signature and implementation handling null Pointer Errors call chain uses extensions. Whatever you need with function returns a result ( ) and run ( also! Than also ( ) return whatever block returns the argument its speed, a “ run ” operator can helpful!, followed By exploring their differences when nesting the other functions, you will to... ” operator can be said as an alternative to Java for Android development it easy very things! ( receiver ) whereas apply needs one that makes you a clear idea about.. Function will print the retrieved person ’ s look at both languages.... Greater results s combine the let and run functions together need to memorize 2 things how., followed By exploring their differences in a matrix is protected under the Apache 2.! Followed By exploring their differences ’ t support the it keyword a particular type and sets scope. Have used Kotlin for development have most likely encountered the set of useful from!

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