The standard approach in Kotlin to check for a null or an empty string … However, when you want to assign null, the compiler will protest with an error: “Null can not be a value of a non-null type String”. Kotlin let is a scoping function wherein the variables declared inside the expression cannot be used outside. Coping with Kotlin's Scope Functions. To use the nullable type, I use a workaround based on the private serialized string and typed getter/setter. Input: Hello World Output: dlroW olleH Input: Hi Ram! Use a temp variable result that stores reversed string. Hence let is inevitably being understood that it is the replacement of null check e.g. 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. isEmpty is the same as comparing to zero string (value Similarly, in Kotlin, I can’t really see why: Output: Reversed: !maR iH 1. Environment Kotlin 1.2.0 Empty Empty means no-content. If you look at the code for String.Empty it actual refers to “” in the background so, like @ilogico, I could never understand the reason why some people insisted on using String.Empty instead. Kotlin program of using let – Kotlin | Check for empty string: Here, we are going to learn how to check whether a given string is an empty, blank or NULL string in Kotlin programming language? I wrote about their difference. Returns 0 if the object is equal to the specfied object. Unfortunately, not every API sends valid JSON. Since literals in Kotlin are implemented as instances of String class, you can use several methods and properties of this class.. length property - returns the length of character sequence of an string. var variable_name = String() String elements and templates – String Element – The character, digit or any other symbol present in string is called as element of a String. Example: Input: str = "" Output: True The library actually contains functions isNullOrEmpty, and isNullOrBlank, which checks whether string is null, or empty, or blank. Few String Properties and Functions. ; compareTo function - compares this String (object) with the specified object. val firstName: String? Sometimes, it sends an empty string instead null. Iterate given string … Kotlin allows developers to assign a sample String and get its length. Kotlin let. = null firstName?.let { println(it.toUpperCase()) } Here, the variable firstName is null, so the lambda expression is not executed to convert the string to Upper Case letters. With the introduction of null safety in Kotlin, everybody now know this special standard function let{...}. Specifically for this task, I have to swap the name in order to let you implement it yourself. You probably already heard about them and it's also likely that you even used some of them yet. Kotlin String has methods, isBlank() and isEmpty(). let takes the object it is invoked upon as the parameter and returns the result of the lambda expression. Program to Reverse a string Pseudo Algorithm. The lambda expression present inside the let is executed only if the variable firstName is not null. An example demonstrating kotlin let function is given below. This article explores different ways to check if a string is empty or null in Kotlin. Submitted by IncludeHelp, on April 27, 2020 . Now, let’s look at a nullable String type: if… Creating an empty String: To create an empty string in Kotlin, we need to create an instance of String class. 1. isNullOrEmpty() function. Initialize it with empty string. Write a Kotlin Program to reverse string with example. As you can see, String is a non-null type. Functions in Kotlin are very important and it's much fun() to use them. Given a string, we have to check whether it is an empty, blank or NULL string. 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