Kotlin has some really cool extension functions as part of the Standard library. This means that Kotlin’s equivalent for flatMap() and map() are similar. This solution by Jayson Minard seems to have little overheads, but need to create multiple extensions to support different number of … but before figuring out the difference among both, let… There are still few techniques for using or accessing the nullable variable. One special collection of relevant functions can be described as "scope functions" and they are part of the Kotlin standard library: let, run, also, apply and with. Dealing with optionals. As there is no constructor as String(“”) in Kotlin, all string comparison will give true if the content will be equal. on Kotlin? Handling every nullable reference in such way could be cumbersome. Si es null evitaremos una excepción. Java types which have these nullability annotations are represented as actual nullable or non-null Kotlin types instead of platform types. Null safety is one of the best features of Kotlin. Coping with Kotlin's Scope Functions. Reference: Kotlin docs So, in Kotlin, a normal property can’t hold a null value. Notice that you have to go out of your way to throw a NullPointerException in Kotlin - otherwise, the third example below would have just returned a null. Nullかもしれない値の三項演算的なこと. If you are familiar with Java, then must have encountered with NullPointerException and to remove this or in other words, we can say that to safely deal with this NullPointerException, the developers of Kotlin introduced Null safety. Thought there won’t be null crashes if you are not using !! You probably already heard about them and it's also likely that you even used some of them yet. Access 7000+ courses for 60 days FREE: https://pluralsight.pxf.io/c/1291657/424552/7490 Kotlin Beginners tutorial. De forma general en Kotlin usaremos let para hacer algo con un objeto en el caso de que éste no sea null. With Kotlin’s null system, the value is either present, or null, so there’s nothing to unwrap. So let’s start with some normal java-esque looking null check code. Fortunately, Kotlin has a syntax for “safe calls” – this syntax allows programmers to execute an action only when the specific reference holds a non-null value.. Let’s define two data classes to illustrate this feature: Let’s focus on one of these functions,let, in order to write safer code and less boilerplate. Solution 4. One of them is safe call ?. There’s no point in optimizing code when comparing to null explicitly. Kotlin’s collection API is built on top of Java’s collection API but it fully supports nullability on Collections. Working With Nullable Types Null Check. Functions in Kotlin are very important and it's much fun() to use them. a == null will be automatically translated to a === null as null is a reference and at the end, it will a reference check. Nullability and Collections. 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