Kotlin 容器

集合Set/MutableSet

集合是一种最简单的容器，具备以下特点：
1> 容器内部元素不按顺序排列，因此无法进行下标金星访问
2>容器内部元素存在唯一性，通过哈希值校验是否存在相同的元素，若存在将其覆盖
for 循环

class MainActivity : AppCompatActivity() {
    private var goodsMap: Map<String, String> = mapOf("苹果" to "iphone 8", "华为" to "Mate10", "小米" to "小米6", "魅族" to "魅族 PRO6")
    private var goodsMutMap:MutableMap<String,String> = mutableMapOf(Pair("苹果","iphone 8"), Pair("华为","Mate10"),
            Pair("小米","小米6"),Pair("魅族","魅族 PRO6"))

    @SuppressLint("SetTextI18n")
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        btn_set_for.setOnClickListener { v ->
            var desc = ""
            for (item in satellites.indices) {
                desc = "${desc}名称：${item}\n"
            }
            text_show.text = "显示的星球数量${satellites.size}\n$desc"
        }
    }
}

效果

22.png