Kotlin 学习之Idioms

创建DTO(POJO/POCO)

data class Customer(val name: String, val email: String, val company: String)

该类提供给如下功能：

• getters(如果变量为var，则还会生成对应的setters)
• equals()
• hashCode()
• toString()
• copy()
• component1(),component2(), …,

函数参数的默认值

fun foo(a: Int = 0, b: String = "test") {
    println("a is $a,b is $b")
}

foo() // a is 0,b is test
foo(1) // a is 1,b is test
foo(1, "success") // a is 1,b is success

过滤列表

    val list: List<Int> = listOf(1, 2, 4, 5, 1, 3)
    val newList = list.filter { x -> x > 2 } 
    // val newList = list.filter { it > 2 }
    println(newList) // [2, 4, 2]