One of my favorite things about Kotlin is the when expression. Its like a combination of an if and a switch you might be familiar with from Java. Performance is that of a standard if statement, , but it reads better and is more functional. Here is a quick example that handles specific values, ranges, and anything beyond.

My favorite ways to use when is to have it return a value based on a condition. Here is an example where I get a string based on the value of an enum.

Another way to use when is more like an if else statement. I generally don't use there because it can lead to comprehension issues. Here is an example where a mammal weighing more than 300 it would never reach the print statement, even though you might expect it to.