However, you need to use the mutable map type in order to create a map that can be edited. Kotlin does give users the ability to create mutable maps, or maps that can be edited after creation.

This means that entries cannot be edited, deleted, or changed in any way after they have been created. It is important to note that Kotlin maps are immutable by default.

In Kotlin, key/value pairs are called entries. However, values do not have to be unique, and they can be paired with multiple different keys in a single map. Every key in a map must be unique, and it can only be associated with one value. In Kotlin, maps can store zero or more key/value pairs. Maps are used to store collections of key/value pairs. In Kotlin, these structures are called maps. Some programming languages call these data structures associative arrays or dictionaries. However, not all programming languages refer to these structures as maps. In the field of computer science, maps are commonly used as a way to structure data. Let’s take a look at what a Kotlin map is and how it is used. If you want an informative overview of Kotlin maps, this post is for you. This topic is very technical in nature, but we won’t delve too deeply into the technicalities. Maps are an important part of Kotlin, and to better understand this programming language and its capabilities, it is important to understand what a Kotlin map is and how it can be effectively used in the development of Android apps. However, in your case you're dealing with an Array, which is a mutable data structure, so the alternative is to use an old-style loop to iteratively transform its items (you can apply the same logic with MutableList or other mutable data structures using an Iterator to update values).If you’re interested in Android mobile app development, you may have come across the topic Kotlin map. So, to get the expected result you should do something like: val doubled = someArray.map įrom what I know there's no built-in function allowing you to map items in-place. Returns a list containing the results of applying the given transform function to each element in the original array. From the documentation, map doesn't modify the items in place but rather returns a List containing the result of the mapping function applied to all the items:

Kotlin map for each