F# - 集合(Sets)

F#中的集合(Sets)是一种数据结构，它是无序的。

创建集合

可以通过以下方式创建集-

• 通过使用Set.empty创建一个空集,并使用添加功能添加项。
• 将序列和列表转换为集合。

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]

基本操作

下表显示了集合的基本操作-

链接：https://www.learnfk.comhttps://www.learnfk.com/fsharp/fsharp-sets.html

来源：LearnFk无涯教程网

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