F# - 可变列表

List<'T> 类表示一个强类型对象列表，可以通过索引访问。

它是 List 类的可变对应物。它类似于数组，因为它可以通过索引访问，但是，与数组不同的是，列表可以调整大小。因此，您无需在声明期间指定大小。

创建可变列表

使用new关键字并调用列表的构造函数来创建列表。以下示例演示了这一点：

(* Creating a List *)
open System.Collections.Generic

let booksList = new List<string>()
booksList.Add("Gone with the Wind")
booksList.Add("Atlas Shrugged")
booksList.Add("Fountainhead")
booksList.Add("Thornbirds")
booksList.Add("Rebecca")
booksList.Add("Narnia")

booksList |> Seq.iteri (fun index item -> printfn "%i: %s" index booksList.[index])

编译并执行程序时，将产生以下输出：

0: Gone with the Wind
1: Atlas Shrugged
2: Fountainhead
3: Thornbirds
4: Rebecca
5: Narnia

List(T) 类

List(T) 类表示一个强类型对象列表，可以通过索引访问。它提供用于搜索、排序和操作列表的方法。

下表提供了 List(T) 类的属性、构造函数和方法：

属性

构造函数

方法

示例

(* Creating a List *)
open System.Collections.Generic

let booksList = new List<string>()
booksList.Add("Gone with the Wind")
booksList.Add("Atlas Shrugged")
booksList.Add("Fountainhead")
booksList.Add("Thornbirds")
booksList.Add("Rebecca")
booksList.Add("Narnia")

printfn"Total %d books" booksList.Count
booksList |> Seq.iteri (fun index item -> printfn "%i: %s" index booksList.[index])
booksList.Insert(2, "Roots")

printfn("after inserting at index 2")
printfn"Total %d books" booksList.Count

booksList |> Seq.iteri (fun index item -> printfn "%i: %s" index booksList.[index])
booksList.RemoveAt(3)

printfn("after removing from index 3")
printfn"Total %d books" booksList.Count

booksList |> Seq.iteri (fun index item -> printfn "%i: %s" index booksList.[index])

编译并执行程序时，将产生以下输出：

Total 6 books
0: Gone with the Wind
1: Atlas Shrugged
2: Fountainhead
3: Thornbirds
4: Rebecca
5: Narnia
after inserting at index 2
Total 7 books
0: Gone with the Wind
1: Atlas Shrugged
2: Roots
3: Fountainhead
4: Thornbirds
5: Rebecca
6: Narnia
after removing from index 3
Total 6 books
0: Gone with the Wind
1: Atlas Shrugged
2: Roots
3: Thornbirds
4: Rebecca
5: Narnia