📅 最后修改于: 2020-11-21 06:50:05 🧑 作者: Mango
F＃中的集合是一种数据结构，它充当项目的集合，而不保留项目的插入顺序。集不允许将重复的条目插入到集合中。
可以通过以下方式创建集-
以下程序演示了这些技术-
(* creating sets *)
let set1 = Set.empty.Add(3).Add(5).Add(7). Add(9)
printfn"The new set: %A" set1
let weekdays = Set.ofList ["mon"; "tues"; "wed"; "thurs"; "fri"]
printfn "The list set: %A" weekdays
let set2 = Set.ofSeq [ 1 .. 2.. 10 ]
printfn "The sequence set: %A" set2
编译并执行程序时，将产生以下输出-
The new set: set [3; 5; 7; 9]
The list set: set ["fri"; "mon"; "thurs"; "tues"; "wed"]
The sequence set: set [1; 3; 5; 7; 9]
下表显示了集合的基本操作-
| Value | Description |
|---|---|
| add : ‘T → Set<‘T> → Set<‘T> | Returns a new set with an element added to the set. No exception is raised if the set already contains the given element. |
| contains : ‘T → Set<‘T> → bool | Evaluates to true if the given element is in the given set. |
| count : Set<‘T> → int | Returns the number of elements in the set. |
| difference : Set<‘T> → Set<‘T> → Set<‘T> | Returns a new set with the elements of the second set removed from the first. |
| empty : Set<‘T> | The empty set for the specified type. |
| exists : (‘T → bool) → Set<‘T> → bool | Tests if any element of the collection satisfies the given predicate. If the input function is predicate and the elements are i0…iN, then this function computes predicate i0 or … or predicate iN. |
| filter : (‘T → bool) → Set<‘T> → Set<‘T> | Returns a new collection containing only the elements of the collection for which the given predicate returns true. |
| fold : (‘State → ‘T → ‘State) → ‘State → Set<‘T> → ‘State | Applies the given accumulating function to all the elements of the set. |
| foldBack : (‘T → ‘State → ‘State) → Set<‘T> → ‘State → ‘State | Applies the given accumulating function to all the elements of the set. |
| forall : (‘T → bool) → Set<‘T> → bool | Tests if all elements of the collection satisfy the given predicate. If the input function is p and the elements are i0…iN, then this function computes p i0 && … && p iN. |
| intersect : Set<‘T> → Set<‘T> → Set<‘T> | Computes the intersection of the two sets. |
| intersectMany : seq |
Computes the intersection of a sequence of sets. The sequence must be non-empty. |
| isEmpty : Set<‘T> → bool | Returns true if the set is empty. |
| isProperSubset : Set<‘T> → Set<‘T> → bool | Evaluates to true if all elements of the first set are in the second, and at least one element of the second is not in the first. |
| isProperSuperset : Set<‘T> → Set<‘T> → bool | Evaluates to true if all elements of the second set are in the first, and at least one element of the first is not in the second. |
| isSubset : Set<‘T> → Set<‘T> → bool | Evaluates to true if all elements of the first set are in the second. |
| isSuperset : Set<‘T> → Set<‘T> → bool | Evaluates to true if all elements of the second set are in the first. |
| iter : (‘T → unit) → Set<‘T> → unit | Applies the given function to each element of the set, in order according to the comparison function. |
| map : (‘T → ‘U) → Set<‘T> → Set<‘U> | Returns a new collection containing the results of applying the given function to each element of the input set. |
| maxElement : Set<‘T> → ‘T | Returns the highest element in the set according to the ordering being used for the set. |
| minElement : Set<‘T> → ‘T | Returns the lowest element in the set according to the ordering being used for the set. |
| ofArray : ‘T array → Set<‘T> | Creates a set that contains the same elements as the given array. |
| ofList : ‘T list → Set<‘T> | Creates a set that contains the same elements as the given list. |
| ofSeq : seq<‘T> → Set<‘T> | Creates a new collection from the given enumerable object. |
| partition : (‘T → bool) → Set<‘T> → Set<‘T> * Set<‘T> | Splits the set into two sets containing the elements for which the given predicate returns true and false respectively. |
| remove : ‘T → Set<‘T> → Set<‘T> | Returns a new set with the given element removed. No exception is raised if the set doesn’t contain the given element. |
| singleton : ‘T → Set<‘T> | The set containing the given element. |
| toArray : Set<‘T> → ‘T array | Creates an array that contains the elements of the set in order. |
| toList : Set<‘T> → ‘T list | Creates a list that contains the elements of the set in order. |
| toSeq : Set<‘T> → seq<‘T> | Returns an ordered view of the collection as an enumerable object. |
| union : Set<‘T> → Set<‘T> → Set<‘T> | Computes the union of the two sets. |
| unionMany : seq |
Computes the union of a sequence of sets. |
以下示例演示了上述某些功能的用法-
let a = Set.ofSeq [ 1 ..2.. 20 ]
let b = Set.ofSeq [ 1 ..3 .. 20 ]
let c = Set.intersect a b
let d = Set.union a b
let e = Set.difference a b
printfn "Set a: "
Set.iter (fun x -> printf "%O " x) a
printfn""
printfn "Set b: "
Set.iter (fun x -> printf "%O " x) b
printfn""
printfn "Set c = set intersect of a and b : "
Set.iter (fun x -> printf "%O " x) c
printfn""
printfn "Set d = set union of a and b : "
Set.iter (fun x -> printf "%O " x) d
printfn""
printfn "Set e = set difference of a and b : "
Set.iter (fun x -> printf "%O " x) e
printfn""
编译并执行程序时，将产生以下输出-
Set a:
1 3 5 7 9 11 13 15 17 19
Set b:
1 4 7 10 13 16 19
Set c = set intersect of a and b :
1 7 13 19
Set d = set union of a and b :
1 3 4 5 7 9 10 11 13 15 16 17 19
Set e = set difference of a and b :
3 5 9 11 15 17