在F中使用CsvProvider#

我是F#的初学者，我正在尝试使用CsvProvider并重现这里给出的示例

所以在F#interactive中，我输入

>type Stocks = CsvProvider<"MSFT.csv">;;

type Stocks = CsvProvider<...>

> let msft = CsvProvider<"MSFT.csv">.GetSample();;

val msft : CsvProvider<...>

> msft;;
val it : CsvProvider<...> =
  FSharp.Data.Runtime.CsvFile`1[System.Tuple`1[System.String]]

    {Headers = Some [|"MSFT.csv"|];
 NumberOfColumns = 1;
 Quote = '"';
 Rows = seq [];
 Separators = ",";}

> let firstRow = msft.Rows |> Seq.head;;
System.ArgumentException: The input sequence was empty.
Parameter name: source
>    at Microsoft.FSharp.Collections.SeqModule.Head[T](IEnumerable`1 source)
   at <StartupCode$FSI_0044>.$FSI_0044.main@()
Stopped due to error

请帮忙！！！我已经试了好几个小时了！谢谢

编辑：以下是F#interactive的完整日志

Microsoft (R) F# Interactive version 14.0.23020.0
Copyright (c) Microsoft Corporation. All Rights Reserved.

For help type #help;;

> #r "C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\packages\FSharp.Data.2.2.5\lib\portable-net40+sl5+wp8+win8\FSharp.Data.dll"
open FSharp.Data;;

--> Referenced 'C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\packages\FSharp.Data.2.2.5\lib\portable-net40+sl5+wp8+win8\FSharp.Data.dll'

> open FSharp.Data;;
> #I "C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I";;

--> Added 'C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I' to library include path

> let msft = CsvProvider<"MSFT.csv">.GetSample();;

val msft : CsvProvider<...>

> msft;;
val it : CsvProvider<...> =
  FSharp.Data.Runtime.CsvFile`1[System.Tuple`1[System.String]]
    {Headers = Some [|"MSFT.csv"|];
     NumberOfColumns = 1;
     Quote = '"';
     Rows = seq [];
     Separators = ",";}
> let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;

  let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;
  ---------------------------------------------------------------------------------------------------^^^^^^^^^

stdin(7,100): error FS0039: The field, constructor or member 'GetSample' is not defined
> let msft = CsvProvider<"MSFT.csv">.GetSample();;

val msft : CsvProvider<...>

> let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;

  let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;
  ---------------------------------------------------------------------------------------------------^^^^^^^^^

stdin(9,100): error FS0039: The field, constructor or member 'GetSample' is not defined
> 

Microsoft（R）F#交互式版本14.0.23020.0
版权所有（c）微软公司。版权所有。
如需帮助，请键入#help；；
>#r“C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo-Stanford I\packages\Fsharp.Data.2.2.5\lib\portable-net40+sl5+wp8+win8\Fsharp.Data.dll”
打开FSharp.Data；；
-->引用的“C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo-Stanford I\packages\Fsharp.Data.2.2.5\lib\portable-net40+sl5+wp8+win8\Fsharp.Data.dll”
>打开FSharp.Data；；
>#I“C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo-Stanford I”；；
-->将“C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I”添加到库包含路径
>设msft=CsvProvider.GetSample（）；；
val msft:CsvProvider
>msft；；
val it:CsvProvider=
FSharp.Data.Runtime.CsvFile`1[System.Tuple`1[System.String]]
{Headers=Some[|“MSFT.csv”|]；
NumberOfColumns=1；
引号=“”；
行=顺序[]；
分隔符=“，”；}
>设msft=CsvProvider.GetSample（）；；
设msft=CsvProvider.GetSample（）；；
---------------------------------------------------------------------------------------------------^^^^^^^^^
stdin（7100）：错误FS0039:未定义字段、构造函数或成员“GetSample”
>设msft=CsvProvider.GetSample（）；；
val msft:CsvProvider
>设msft=CsvProvider.GetSample（）；；
设msft=CsvProvider.GetSample（）；；
---------------------------------------------------------------------------------------------------^^^^^^^^^
stdin（9100）：错误FS0039:未定义字段、构造函数或成员“GetSample”
> 

我猜F#Interactive在当前目录中查找

MSFT.csv

文件时有困难。您可以使用

文本指定相对于当前目录的完整路径：

let [<Literal>] Sample = __SOURCE_DIRECTORY__ + "\\MSFT.csv"
type Stocks = CsvProvider<Sample>

let[]Sample=\uuuuuu源目录\uuuuu+“\\MSFT.csv”
类型股票=CsvProvider

然后可以调用
Stocks.GetSample（）
来读取文件

这种错误有时发生在F#Interactive中，尤其是在不同文件夹中的文件之间切换时（我认为F#Interactive记得上次执行命令的文件夹，但我认为它的行为并不总是如预期的那样）。
CSV文件的内容是什么？（我怀疑它是空的）这是我在http链接上找到的同一个文件。它是一个321ko文件。这是前两行日期，打开、高、低、关闭、音量、调整关闭2012-01-27,29.45,29.53,29.17,29.2344187700,29.23 2012-01-26,29.61,29.70,29.40,29.5049102800,29.50。我无法重现这个问题。当你下载该文件时，如果你在Windows上，你做了什么e确定您打开了文件的属性并取消了阻止？出于安全原因，从internet下载的文件通常会被“锁定”，这可能也会影响CSV提供商。我确实在Windows上，但该文件没有被阻止。我对其他文件也有同样的问题。我可以在写字板中毫无问题地打开它们。为了清晰起见我已经在F#interactive中复制/粘贴了整个会话。当进入完整路径时，您需要避开反斜杠。您可以编写
CsvProvider<@“C:\foo.csv”>
或
CsvProvider
>让msft=CsvProvider.GetSample（）；让msft=CsvProvider.GetSample（）；；---------------------------------------------------------------------------------------------------------------stdin（11101）：错误FS0039:未定义字段、构造函数或成员“GetSample”
>let msft=CsvProvider.GetSample（）；；；----------------------------------------------------------------------------------------------------------------------------------------^^^ stdin（12112）：错误FS0010:在引号文字中的这一点或之前的结构化构造不完整。应为引号结尾或其他标记。
在
@
符号-
CsvProvider<@…“>
。这有点傻，但这是F#解析器工作方式的产物。
Microsoft (R) F# Interactive version 14.0.23020.0
Copyright (c) Microsoft Corporation. All Rights Reserved.

For help type #help;;

> #r "C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\packages\FSharp.Data.2.2.5\lib\portable-net40+sl5+wp8+win8\FSharp.Data.dll"
open FSharp.Data;;

--> Referenced 'C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\packages\FSharp.Data.2.2.5\lib\portable-net40+sl5+wp8+win8\FSharp.Data.dll'

> open FSharp.Data;;
> #I "C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I";;

--> Added 'C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I' to library include path

> let msft = CsvProvider<"MSFT.csv">.GetSample();;

val msft : CsvProvider<...>

> msft;;
val it : CsvProvider<...> =
  FSharp.Data.Runtime.CsvFile`1[System.Tuple`1[System.String]]
    {Headers = Some [|"MSFT.csv"|];
     NumberOfColumns = 1;
     Quote = '"';
     Rows = seq [];
     Separators = ",";}
> let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;

  let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;
  ---------------------------------------------------------------------------------------------------^^^^^^^^^

stdin(7,100): error FS0039: The field, constructor or member 'GetSample' is not defined
> let msft = CsvProvider<"MSFT.csv">.GetSample();;

val msft : CsvProvider<...>

> let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;

  let msft = CsvProvider<"C:\Users\Fagui\Documents\GitHub\Learning Fsharp\Algo Stanford I\MSFT.csv">.GetSample();;
  ---------------------------------------------------------------------------------------------------^^^^^^^^^

stdin(9,100): error FS0039: The field, constructor or member 'GetSample' is not defined
> 

let [<Literal>] Sample = __SOURCE_DIRECTORY__ + "\\MSFT.csv"
type Stocks = CsvProvider<Sample>