val firstName: String? 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? if… = 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. 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. Input: Hello World Output: dlroW olleH Input: Hi Ram! Program to Reverse a string Pseudo Algorithm. 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. Example: Input: str = "" Output: True Submitted by IncludeHelp, on April 27, 2020 . To use the nullable type, I use a workaround based on the private serialized string and typed getter/setter. Use a temp variable result that stores reversed string. Kotlin allows developers to assign a sample String and get its length. But you use such functions in Kotlin from the standard library by default. Functions in Kotlin are very important and it's much fun() to use them. Kotlin let. Environment Kotlin 1.2.0 Empty Empty means no-content. Iterate given string … Few String Properties and Functions. Specifically for this task, I have to swap the name in order to let you implement it yourself. Kotlin let is a scoping function wherein the variables declared inside the expression cannot be used outside. The standard approach in Kotlin to check for a null or an empty string … Output: Reversed: !maR iH 1. isEmpty is the same as comparing to zero string (value As you can see, String is a non-null type. 1. isNullOrEmpty() function. Given a string, we have to check whether it is an empty, blank or NULL string. Sometimes, it sends an empty string instead null. Unfortunately, not every API sends valid JSON. Similarly, in Kotlin, I can’t really see why: Creating an empty String: To create an empty string in Kotlin, we need to create an instance of String class. ; compareTo function - compares this String (object) with the specified object. I wrote about their difference. let takes the object it is invoked upon as the parameter and returns the result of the lambda expression. This article explores different ways to check if a string is empty or null in Kotlin. 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”. Write a Kotlin Program to reverse string with example. Returns 0 if the object is equal to the specfied object. Initialize it with empty string. The library actually contains functions isNullOrEmpty, and isNullOrBlank, which checks whether string is null, or empty, or blank. Kotlin String has methods, isBlank() and isEmpty(). Kotlin program of using let – A custom serializer for classes, containing many members, is more complex than this workaround. 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. Coping with Kotlin's Scope Functions. An example demonstrating kotlin let function is given below. 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. 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