2011-01-21 08:17
横刀天笑
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F# part one:function,list,option,seq,pattern match,rec function etc.
1: let x = 5
2:
3: val x : int = 5
4:
5: open System.Net
6: open System.IO
7:
8: //method
9: let http (url:string) =
10: let req = WebRequest.Create(url)
11: let resp = req.GetResponse()
12: let stream = resp.GetResponseStream()
13: let reader = new StreamReader(stream)
14: reader.ReadToEnd()
15:
16: //method type
17: val http : string -> string
18:
19: let html = http "http://www.google.com"
20:
21: val html : string = "<html document>"
22:
23: // |> operator
24: let html1 = "http://www.google.com" |> http
25:
26: //string list
27: let sites = ["http://www.google.com";"http://www.baidu.com";"http://www.bing.com"]
28:
29: val sites : string list = ["http://www.google.com";"http://www.baidu.com";"http://www.bing.com"]
30:
31: //map method
32: let contents = sites |> List.map http
33:
34: //list
35: ["";"";""]
36: //array
37: [|"";"";""|]
38: //option
39: Some(4,5,6)
40: None
41: //seq
42: seq{1..100}
43: val it : seq<int> = seq[1;2;3;4;..]
44: seq{1..5..100}
45: seq{for i in 1 to 100 -> i*i}
46: //tuple
47: ("keyword1",5)
48:
49: //rec function
50: let rec length l =
51: match l with
52: | [] -> 0
53: | h :: t -> 1 + length t
54:
55: //pattern match
56: match aList with
57: |[] -> 0
58: |h :: t -> 1 + length t
59:
60: match aOption with
61: | Some(a,b) -> printfn "%s %s" a b
62: | None -> printfn "nothing"
63:
64: //function value
65: List.map (fun x -> x*x - 5) [5;6;7;8]
