F＃集

F＃中的集合是一種數(shù)據(jù)結(jié)構(gòu)，用作項目的集合，而不保留插入項目的順序。 集合不允許將重復(fù)條目插入到集合中。

創(chuàng)建集

集可以通過以下方式創(chuàng)建

• 通過創(chuàng)建使用Set.empty空集和添加使用add函數(shù)項。
• 轉(zhuǎn)換序列和列表來套。

下面是程序演示

(* 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

當你編譯和執(zhí)行程序，它產(chǎn)生以下輸出 

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]

集的基本操作

下表顯示了集的基本操作 

下面的例子演示了上述一些功能的使用 

例

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""

當你編譯和執(zhí)行程序，它產(chǎn)生以下輸出 

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