What is the difference between using 'let' and 'also' keywords in programming?

In the context of Kotlin (Android), the keywords let and also are extension functions for working with objects, but they have different purposes and behaviors:

• let is used for transforming an object or performing operations with it, returning the result of the last expression in the lambda. Inside the lambda, the object is accessible as it.

• also is used for performing additional actions with the object (e.g., logging, debugging), returning the object itself unchanged. Inside the lambda, the object is also accessible as it.

Example:

val number = "123"

// let transforms the string into a number
val length = number.let {
    println("String length: ${it.length}")
    it.length
}

// also performs an action, returning the original object
val newNumber = number.also {
    println("Original value: $it")
}.toInt()

Summary:

• let is useful when you need to get the result of processing an object.
• also is convenient for side effects without modifying the object.