When doing this the let code block will only be executed if the object is not null. The let function is useful when you wish to perform a null safe operation on an Object by using the the safe call operator ?.

Readability here is a matter of preference, and may be preferred. If you are using IntelliJ it will give a warning saying the call to let is redundant.

In the above case there is no reason to use let. To answer your question as to which code is more preferable, it really depends on what you are using the scope function for. Other scope functions like apply will return the context object instead.īecause let returns whatever the lambda block evaluates to, it is most suited to performing a mapping of some kind: var upperStr = str.let Īpply is a more suited function for what you are doing. The return value is whatever is returned from the lambda code block. In the case of let the context object is referenced by the it keyword as opposed to the this keyword. They are all very similar but they differ in terms of how the context object is referenced and the value that is returned. Their usages range from but are not exclusive to initialization and mapping. There are five of them: let, run, with, apply, and also. Let is one of Kotlin's Scope functions which allow you to execute a code block within the context of an object.

Null safe kotlin