创建自定义对象F＃的列表

Question

I have a custom object declared as follows:

class Listing : NSObject {
var from : Date?
var to : Date?
var pricePerNight : Int?
....
}

I then create an empty list of these objects like this:

var myListings = [Listing]()

I am now trying to create the same functionality using F# . I have defined an interface as follows:

type Listing = 

abstract member fromDate : NSDate with get,set
abstract member toDate : NSDate with get,set
abstract member pricePerNight : int with get,set
...

And then I did this:

    let listings : List<Listing> = List.Empty

Is my understanding correct?

Answer 1

F# list (which is not the same as Swift/C# List ) is an immutable, singly linked list. It is more idiomatic as a F# data structure, has better support in the language (pattern matching, etc.), and since it's immutable you can safely make it public or share it between different threads. However, it is slower than many other data structures.

The F# equivalent of a Swift/C# List (in fact, it's exactly the same as a C# List ) is called ResizeArray , which is a mutable array of automatically variable size. If you need your collection to be mutable, it's probably the data structure you want.

Either can be the correct choice, depending on what you want to do.