Kotlin Functions

for.kt

for ((index, value) in array.withIndex()) {
    println("the element at $index is $value")
}

for (index in array.indices){
    println("the element at $index is ${array[index]}")
}

for (index in 0 until array.size){
    println("the element at $index is ${array[index]}")
}

Function.kt

class MyClass {
    fun test() {
        val str: String = "..."
        val result = str.xxx {
            print(this) // Receiver
            print(it) // Argument
            42 // Block return value
        }
    }
}

╔══════════╦═════════════════╦═══════════════╦═══════════════╗
║ Function ║ Receiver (this) ║ Argument (it) ║    Result     ║
╠══════════╬═════════════════╬═══════════════╬═══════════════╣
║ let      ║ this@MyClass    ║ String("...") ║ Int(42)       ║
║ run      ║ String("...")   ║ N\A           ║ Int(42)       ║
║ run*     ║ this@MyClass    ║ N\A           ║ Int(42)       ║
║ with*    ║ String("...")   ║ N\A           ║ Int(42)       ║
║ apply    ║ String("...")   ║ N\A           ║ String("...") ║
║ also     ║ this@MyClass    ║ String("...") ║ String("...") ║
╚══════════╩═════════════════╩═══════════════╩═══════════════╝