# Collections

```kotlin
val list = listOf(1, 2, 3)
val mutableListOf = mutableListOf(1, 2, 3)

val set = setOf(1, 2, 3)
val mutableSet = mutableSetOf(1, 2, 3)

val map = mapOf(1 to "1", 2 to "2", 3 to "3")
val mutableMap = mutableMapOf(1 to "1", 2 to "2", 3 to "3")
```

* Kotlin 은 Java 와 다르게 mutable, immutable 2가지의 collection 이 존재한다.
* mutable 은 변경 가능한 collection 을 말한다.
* immutable 은 변경 불가능한 collection 을 말한다.
* mutable prefix 가 없는 자료구조는 기본적으로 immutable 이다.


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