In addition to if, for, and while loops, Kotlin also has a control flow option called when. The ‘when’ expression acts just like a switch operator you might see in other languages. The basic structure looks like this: Some notes about this switch structure: The first line uses the key word when followed by a … Continue reading Kotlin: How to use the ‘when’ expression

Kotlin’s built-in .filter() function is meant to iterate through any iterable collection type, (lists, sets, or maps) and check each element of the collection against some criteria (aka “predicate”). If the element matches the predicate, meaning the boolean result is true, then the element is added to a result collection of the same type that … Continue reading Kotlin: How to use .filter( ), ‘it’ key word, and arrow ‘->’ operator

The Kotlin “not-null assertion operator” is expressed as two exclamation points. !! that appear at the end of a variable name. For example: myVariable!! Here is what the Kotlin documentation says about this operator: Here is what I learned about the not-null assertion operator after a little bit of experimentation: The difference between b and … Continue reading Kotlin: How to understand the not-null assertion operator (!!)

Here are some online web apps that people have written that make it possible to test your Kotlin code online. play.kotlinlang.orghttp://play.kotlinlang.org/ JDOODLEhttp://jdoodle.com/ tutorialspointhttps://tutorialspoint.com

When starting on the journey of learning the Kotlin language, it is a good idea to get an initial impression of the language by creating and running the simplest possible program in Kotlin. That is what I will describe how to do in this article. The first step assumes that you have already downloaded and … Continue reading Kotlin: How to create a simple Hello World app