F#组合两个序列
我有两个序列,我想以某种方式组合,因为我需要第二个的结果打印在第一个的旁边。该代码当前是playerItems引用列表的位置:F#组合两个序列,f#,functional-programming,sequences,F#,Functional Programming,Sequences,我有两个序列,我想以某种方式组合,因为我需要第二个的结果打印在第一个的旁边。该代码当前是playerItems引用列表的位置: seq state.player.playerItems |> Seq.map (fun i -> i.name) |> Seq.iter (printfn "You have a %s") seq state.player.playerItems |> Seq.map (fun i -> i.desc
seq state.player.playerItems
|> Seq.map (fun i -> i.name)
|> Seq.iter (printfn "You have a %s")
seq state.player.playerItems
|> Seq.map (fun i -> i.description) |> Seq.iter (printfn "Description = %s")
目前的结果是
You have a Keycard
You have a Hammer
You have a Wrench
You have a Screw
Description = Swipe to enter
Description = Thump
Description = Grab, Twist, Let go, Repeat
Description = Twisty poke
然而,我需要它
You have a Keycard
Description = Swipe to enter
You have a Hammer
Description = Thump
任何帮助都将不胜感激。正如Foggy Finder在评论中所说,在您的特定情况下,您确实没有两个序列,您有一个序列,并且您希望为每个项目打印两行,这可以用一个
Seq.iter
来完成,如下所示:
state.player.playerItems // The "seq" beforehand is not necessary
|> Seq.iter (fun player -> printfn "You have a %s\nDescription = %s" player.name player.description)
然而,我也会告诉你两种组合两个序列的方法,当你真的有两个不同的序列的时候。首先,如果要将这两个序列转换为元组序列,可以使用Seq.zip
:
let colors = Seq.ofList ["red"; "green"; "blue"]
let numbers = Seq.ofList [25; 73; 42]
let pairs = Seq.zip colors numbers
printfn "%A" pairs
// Prints: seq [("red", 25); ("green", 73); ("blue", 42)]
如果要以其他方式组合这两个序列而不是生成元组,请使用Seq.map2
并向其传递一个双参数函数:
let colors = Seq.ofList ["red"; "green"; "blue"]
let numbers = Seq.ofList [25; 73; 42]
let combined = Seq.map2 (fun clr num -> sprintf "%s: %d" clr num) colors numbers
printfn "%A" combined
// Prints: seq ["red: 25"; "green: 73"; "blue: 42"]
最后,如果您只想对这两个序列中的每对项目执行一些副作用,那么Seq.iter2
就是您的朋友:
let colors = Seq.ofList ["red"; "green"; "blue"]
let numbers = Seq.ofList [25; 73; 42]
Seq.iter2 (fun clr num -> printfn "%s: %d" clr num)
这将向控制台打印以下三行:
red: 25
green: 73
blue: 42
请注意,在
Seq.iter
函数中,我没有存储结果。这是因为Seq.iter
的结果总是()
,即F#等于void
的“单位”值。(除了它比void
有用得多之外,原因超出了此答案的范围。在堆栈溢出中搜索“[F#]单位”,您应该会找到一些有趣的问题和答案,例如。state.player.playerItems>Seq.iter(有趣的玩家->打印fn“您有%s\n说明=%s”player.name player.description)