プログラミング学習の記録 339.1「『Programming F#』 Chris Smith 著のⅠ部(マルチパラダイムプログラミング),2章(基本事項),4(主要な型),4(集計演算子)-6(Printfn)

開発環境

• Microsoft Windows 7 Home Premium (OS)
• Microsoft Visual Studio 2010(Visual Studio 2010 Shell + F# Community Technology Preview(CTP)(F# Compiler and F# for Visual Studio)) (IDE)
• 言語: F# (A Functional Programming Langage)

「『Programming F#』 Chris Smith 著、Copyright 2010 Chris Smith、ISBN 978-9-596-15364-9、邦題『プログラミング F#』 オライリー・ジャパン刊、ISBN 978-4-87311-466-8」のⅠ部(マルチパラダイムプログラミング)、2章(基本事項)を参考に学習。2.4(主要な型), 2.4.4(集計演算子), 2.4.5(オプション), 2.4.6(Printfn)まで。

FSI(F# Interactive)

Microsoft (R) F# 2.0 Interactive build 4.0.30319.1 Copyright (c) Microsoft Corporation. All Rights Reserved. For help type #help;; > let squares x=x*x;; val squares : int -> int > List.map squares [1 .. 10];; val it : int list = [1; 4; 9; 16; 25; 36; 49; 64; 81; 100] > let multiple x=10*x;; val multiple : int -> int > List.map multiple [1 .. 10];; val it : int list = [10; 20; 30; 40; 50; 60; 70; 80; 90; 100] > let insertCommas (acc : string) item = acc + ", " + item;; val insertCommas : string -> string -> string > List.reduce insertCoomas ["Jack";"Jill";"Jim";"Joe";"Jane"];; List.reduce insertCoomas ["Jack";"Jill";"Jim";"Joe";"Jane"];; ------------^^^^^^^^^^^^ stdin(6,13): error FS0039: The value or constructor 'insertCoomas' is not defined > List.reduce insertCommas["Jack";"Jill";"Jim";"Joe";"Jane"];; List.reduce insertCommas["Jack";"Jill";"Jim";"Joe";"Jane"];; ------------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ stdin(7,13): error FS0597: Successive arguments should be separated by spaces or tupled, and arguments involving function or method applications should be parenthesized > List.reduce insertCommas ["Jack";"Jill";"Jim";"Joe";"Jane"];; val it : string = "Jack, Jill, Jim, Joe, Jane" > let addAccToListItem acc i=acc + i;; val addAccToListItem : int -> int -> int > List.fold addAccToListItem 0 [1;2;3];; val it : int = 6 > Program.fs(4,5): error FS0588: Block following this 'let' is unfinished. Expect an expression. > > val countVowels : string -> int * int * int * int * int > > countVowels "The quick brown fox jumps over the lazy dog";; val it : int * int * int * int * int = (1, 3, 1, 4, 2) > 印刷中 1 印刷中 2 印刷中 3 印刷中 4 印刷中 5 val printNumber : int -> unit > > val isInteger : string -> int option > > isInteger "String";; val it : int option = None > isInteger "1";; val it : int option = Some 1 > val isLessThanZero : int -> bool val containsNegativeNumbers : int list -> int list option > let negativeNumbers=containsNegativeNumbers [6;20;-20;-6;10];; val negativeNumbers : int list option = Some [-20; -6] > Option.get negativeNumbers;; val it : int list = [-20; -6] > let negativeNumbers=numbers[1;2;3;4;5];; let negativeNumbers=numbers[1;2;3;4;5];; --------------------^^^^^^^ C:\Users\Kamimura\AppData\Local\Temp\stdin(5,21): error FS0039: The value or constructor 'numbers' is not defined > let negativeNumbers=numbers [1;2;3;4;5];; let negativeNumbers=numbers [1;2;3;4;5];; --------------------^^^^^^^ C:\Users\Kamimura\AppData\Local\Temp\stdin(6,21): error FS0039: The value or constructor 'numbers' is not defined > let numbers=containsNegativeNumbers [1;2;3;4;5];; val numbers : int list option = None > Option.isSome numbers;; val it : bool = false > Option.isSome negativeNumbers;; val it : bool = true > Option.isNone numbers;; val it : bool = true > Option.isNone negativeNumbers;; val it : bool = false > printf "Hello, " printfn "World!" printfn "Hello, World!";; Hello, World! Hello, World! > val mountain : string = "K2" val height : int = 8611 val units : char = 'm' > K2 は最高 8611m です val it : unit = () > printfn " 整数 = %d" 1.23;; printfn " 整数 = %d" 1.23;; -------------------^^^^ C:\Users\Kamimura\AppData\Local\Temp\stdin(3,20): error FS0001: The type 'float' is not compatible with any of the types byte,int16,int32,int64,sbyte,uint16,uint32,uint64,nativeint,unativeint, arising from the use of a printf-style format string > // 型推論 let inferParams x y z=printfn "x = %f, y=%s, z=%b" x y z;; val inferParams : float -> string -> bool -> unit > let location="Japan";; val location : string = "Japan" > printf "Hello, %s" location sprintf "Hello, %s" location;; Hello, Japan> j ;; j ^ C:\Users\Kamimura\AppData\Local\Temp\stdin(9,1): error FS0039: The value or constructor 'j' is not defined > printf "Hello, %s";; val it : (string -> unit) = <fun:it@11-7> > printf "Hello, %s" location;; Hello, Japanval it : unit = () > sprintf "Hello, %s" location;; val it : string = "Hello, Japan" >

記述するコードの長さによってテキストエディタとFSIを柔軟に使い分けることができるようになってきた。