📅 最后修改于: 2020-11-21 06:53:20 🧑 作者: Mango
List <‘T>类表示可以通过索引访问的对象的强类型列表。
它是List类的可变对等物。它与数组相似，因为它可以由索引访问，但是，与数组不同，可以调整列表的大小。因此，您无需在声明期间指定大小。
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()
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)类表示可以通过索引访问的对象的强类型列表。它提供了搜索，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-
| Property | Description |
|---|---|
| Capacity | Gets or sets the total number of elements the internal data structure can hold without resizing. |
| Count | Gets the number of elements contained in the List(T). |
| Item | Gets or sets the element at the specified index. |
| Constructor | Description |
|---|---|
| List(T)() | Initializes a new instance of the List(T) class that is empty and has the default initial capacity. |
| List(T)(IEnumerable(T)) | Initializes a new instance of the List(T) class that contains elements copied from the specified collection and has sufficient capacity to accommodate the number of elements copied. |
| List(T)(Int32) | Initializes a new instance of the List(T) class that is empty and has the specified initial capacity. |
| Methods | Description |
|---|---|
| Add | Adds an object to the end of the List(T). |
| AddRange | Adds the elements of the specified collection to the end of the List(T). |
| AsReadOnly | Returns a read-only IList(T) wrapper for the current collection. |
| BinarySearch(T) | Searches the entire sorted List(T) for an element using the default comparer and returns the zero-based index of the element. |
| BinarySearch(T, IComparer(T)) | Searches the entire sorted List(T) for an element using the specified comparer and returns the zero-based index of the element. |
| BinarySearch(Int32, Int32, T, IComparer(T)) | Searches a range of elements in the sorted List(T) for an element using the specified comparer and returns the zero-based index of the element. |
| Clear | Removes all elements from the List(T). |
| Contains | Determines whether an element is in the List(T). |
| ConvertAll(TOutput) | Converts the elements in the current List(T) to another type, and returns a list containing the converted elements. |
| CopyTo(T[]) | Copies the entire List(T) to a compatible one-dimensional array, starting at the beginning of the target array. |
| CopyTo(T[], Int32) | Copies the entire List(T) to a compatible one-dimensional array, starting at the specified index of the target array. |
| CopyTo(Int32, T[], Int32, Int32) | Copies a range of elements from the List(T) to a compatible one-dimensional array, starting at the specified index of the target array. |
| Equals(Object) | Determines whether the specified object is equal to the current object. (Inherited from Object.) |
| Exists | Determines whether the List(T) contains elements that match the conditions defined by the specified predicate. |
| Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection (Inherited from Object). |
| Find | Searches for an element that matches the conditions defined by the specified predicate, and returns the first occurrence within the entire List(T). |
| FindAll | Retrieves all the elements that match the conditions defined by the specified predicate. |
| FindIndex(Predicate(T)) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the entire List(T). |
| FindIndex(Int32, Predicate(T)) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the List(T) that extends from the specified index to the last element. |
| FindIndex(Int32, Int32, Predicate(T)) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the first occurrence within the range of elements in the List(T) that starts at the specified index and contains the specified number of elements. |
| FindLast | Searches for an element that matches the conditions defined by the specified predicate, and returns the last occurrence within the entire List(T). |
| FindLastIndex(Predicate(T)) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the entire List(T). |
| FindLastIndex(Int32, Predicate(T)) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the List(T) that extends from the first element to the specified index. |
| FindLastIndex(Int32, Int32, Predicate(T)) | Searches for an element that matches the conditions defined by the specified predicate, and returns the zero-based index of the last occurrence within the range of elements in the List(T) that contains the specified number of elements and ends at the specified index. |
| ForEach | Performs the specified action on each element of the List(T). |
| GetEnumerator | Returns an enumerator that iterates through the List(T). |
| GetHashCode | Serves as the default hash function. (Inherited from Object.) |
| GetRange | Creates a shallow copy of a range of elements in the source List(T). |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| IndexOf(T) | Searches for the specified object and returns the zero-based index of the first occurrence within the entire List(T). |
| IndexOf(T, Int32) | Searches for the specified object and returns the zero-based index of the first occurrence within the range of elements in the List(T) that extends from the specified index to the last element. |
| IndexOf(T, Int32, Int32) | Searches for the specified object and returns the zero-based index of the first occurrence within the range of elements in the List(T) that starts at the specified index and contains the specified number of elements. |
| Insert | Inserts an element into the List(T) at the specified index. |
| InsertRange | Inserts the elements of a collection into the List(T) at the specified index. |
| LastIndexOf(T) | Searches for the specified object and returns the zero-based index of the last occurrence within the entire List(T). |
| LastIndexOf(T, Int32) | Searches for the specified object and returns the zero-based index of the last occurrence within the range of elements in the List(T) that extends from the first element to the specified index. |
| LastIndexOf(T, Int32, Int32) | Searches for the specified object and returns the zero-based index of the last occurrence within the range of elements in the List(T) that contains the specified number of elements and ends at the specified index. |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| Remove | Removes the first occurrence of a specific object from the List(T). |
| RemoveAll | Removes all the elements that match the conditions defined by the specified predicate. |
| RemoveAt | Removes the element at the specified index of the List(T). |
| RemoveRange | Removes a range of elements from the List(T). |
| Reverse() | Reverses the order of the elements in the entire List(T). |
| Reverse(Int32, Int32) | Reverses the order of the elements in the specified range. |
| Sort() | Sorts the elements in the entire List(T) using the default comparer. |
| Sort(Comparison(T)) | Sorts the elements in the entire List(T) using the specified System. Comparison(T). |
| Sort(IComparer(T)) | Sorts the elements in the entire List(T) using the specified comparer. |
| Sort(Int32, Int32, IComparer(T)) | Sorts the elements in a range of elements in List(T) using the specified comparer. |
| ToArray | Copies the elements of the List(T) to a new array. |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
| TrimExcess | Sets the capacity to the actual number of elements in the List(T), if that number is less than a threshold value. |
| TrueForAll | Determines whether every element in the List(T) matches the conditions defined by the specified predicate. |
(* Creating a List *)
open System.Collections.Generic
let booksList = new List()
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