F# -包含数字的自然类型的字符串
F# -包含数字的自然类型的字符串
提问于 2018-05-26 12:43:34
是否有相当于F#的人类排序:自然排序顺序？例如，复制以下示例：
Actual (List.sort) : let strngLst = ["1-5"; "10-15"; "15-20"; "5-10"]
Expected : let strngLst = ["1-5"; "5-10"; "10-15"; "15-20"]请指点？
回答 2
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回答已采纳
发布于 2018-05-27 18:59:10
基于@matekus的评论，最正确的解决方案可能是将AlphaNum排序移植到F#，因此：
let len = String.length
let isnum (s: string) i =
let c = s.Chars i
c >= '0' && c <= '9'
let chunk s f t = (f < len s) && (t < len s) && (isnum s f) = (isnum s t)
let chunkto s f =
let rec to_ s f e = if chunk s f e then to_ s f (e + 1) else e in to_ s f f
let int_of_string str =
let v = ref 0
if System.Int32.TryParse(str, v) then !v else 0
let alphanumcmp a b =
let rec chunkcmp a ai b bi =
let al, bl = len a, len b
if ai >= al || bi >= bl then compare al bl else
let ae, be = chunkto a ai, chunkto b bi
let sa, sb = a.Substring(ai, (ae-ai)), b.Substring(bi, (be-bi))
let cmp = if isnum a ai && isnum b bi then compare (int_of_string sa) (int_of_string sb) else compare sa sb
if cmp = 0 then chunkcmp a ae b be else cmp
in chunkcmp a 0 b 0
type AlphanumComparer() =
interface System.Collections.IComparer with
member this.Compare(x, y) =
alphanumcmp (x.ToString()) (y.ToString())测试：
let names = [ "1000X Radonius Maximus"; "10X Radonius"; "200X Radonius"; "20X Radonius"; "20X Radonius Prime"; "30X Radonius"; "40X Radonius"; "Allegia 50 Clasteron"; "Allegia 500 Clasteron"; "Allegia 51 Clasteron"; "Allegia 51B Clasteron"; "Allegia 52 Clasteron"; "Allegia 60 Clasteron"; "Alpha 100"; "Alpha 2"; "Alpha 200"; "Alpha 2A"; "Alpha 2A-8000"; "Alpha 2A-900"; "Callisto Morphamax"; "Callisto Morphamax 500"; "Callisto Morphamax 5000"; "Callisto Morphamax 600"; "Callisto Morphamax 700"; "Callisto Morphamax 7000"; "Callisto Morphamax 7000 SE";"Callisto Morphamax 7000 SE2"; "QRS-60 Intrinsia Machine"; "QRS-60F Intrinsia Machine"; "QRS-62 Intrinsia Machine"; "QRS-62F Intrinsia Machine"; "Xiph Xlater 10000"; "Xiph Xlater 2000"; "Xiph Xlater 300"; "Xiph Xlater 40"; "Xiph Xlater 5"; "Xiph Xlater 50"; "Xiph Xlater 500"; "Xiph Xlater 5000"; "Xiph Xlater 58" ];;
names |> List.sortWith alphanumcmp |> printf "%A" 结果：
["10X Radonius"; "20X Radonius"; "20X Radonius Prime"; "30X Radonius";
"40X Radonius"; "200X Radonius"; "1000X Radonius Maximus";
"Allegia 50 Clasteron"; "Allegia 51 Clasteron"; "Allegia 51B Clasteron";
"Allegia 52 Clasteron"; "Allegia 60 Clasteron"; "Allegia 500 Clasteron";
"Alpha 2"; "Alpha 2A"; "Alpha 2A-900"; "Alpha 2A-8000"; "Alpha 100";
"Alpha 200"; "Callisto Morphamax"; "Callisto Morphamax 500";
"Callisto Morphamax 600"; "Callisto Morphamax 700"; "Callisto Morphamax 5000";
"Callisto Morphamax 7000"; "Callisto Morphamax 7000 SE";
"Callisto Morphamax 7000 SE2"; "QRS-60 Intrinsia Machine";
"QRS-60F Intrinsia Machine"; "QRS-62 Intrinsia Machine";
"QRS-62F Intrinsia Machine"; "Xiph Xlater 5"; "Xiph Xlater 40";
"Xiph Xlater 50"; "Xiph Xlater 58"; "Xiph Xlater 300"; "Xiph Xlater 500";
"Xiph Xlater 2000"; "Xiph Xlater 5000"; "Xiph Xlater 10000"]val it : unit = ()Stack Overflow用户
发布于 2018-05-26 13:46:13
基于那篇文章中的Python3linder，我会这样做：
open System
open System.Text.RegularExpressions
let sortNicely l =
let convert text =
match Int32.TryParse(text) with
| true, i -> Choice1Of2 i
| false, _ -> Choice2Of2 text
let alphanumKey key =
Regex("([0-9]+)").Split(key) |> Array.map convert
List.sortBy alphanumKey l主要的区别是Choice类型的使用。Python巧妙地在convert中使用动态类型: Python总是认为int小于字符串，所以convert可以返回int或字符串，sort可以做我们想做的事情。但在F#中，我们需要更加明确。我使用了一个受歧视的联合，因为它也能实现我们想要的结果:第一个案例(Choice1Of2)的值总是小于第二个案例(Choice2Of2)的值。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50542901
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