Kotlin Standard Library Cookbook

See also

• This recipe gave us an insight into how Kotlin standard library implementations of ranges for primitives are easy to work with. A problem can appear if we want to traverse non-primitive types using the for loop. However, it turns out we can easily declare a range for any Comparable type. This will be shown in the Building custom progressions to traverse dates recipe.

• As you have noticed, we are using the in operator to specify the object that is being iterated in the loop. However, there are also other scenarios where the in and !in operators can be used together with ranges. We will investigate them in depth in the Using range expressions with flow control statements recipe.