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ExtraTopLevelOperators.fprintf<'T> Function (F#)

The fprintf functions prints to a file using the given format.

Namespace/Module Path: Microsoft.FSharp.Core.ExtraTopLevelOperators

Assembly: FSharp.Core (in FSharp.Core.dll)

// Signature:
fprintf : TextWriter -> TextWriterFormat<'T> -> 'T

// Usage:
fprintf textWriter format

textWriter

Type: TextWriter

format

Type: TextWriterFormat<'T>

This function is named PrintFormatToTextWriter in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.

The following example demonstrates the use of fprintf.


let printNumbersToFile fileName n =
   // "use" will cause the file to be closed when it
   // goes out of scope.
   use file = System.IO.File.CreateText(fileName)
   [ 1 .. n ]
   |> List.iter (fun elem -> fprintf file "%d " elem)
   fprintfn file ""
printNumbersToFile "1to100.txt" 100


The resulting file 1to100.txt contains the following data.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 

Windows 7, Windows Vista SP2, Windows XP SP3, Windows XP x64 SP2, Windows Server 2008 R2, Windows Server 2008 SP2, Windows Server 2003 SP2

F# Runtime

Supported in: 2.0, 4.0

Silverlight

Supported in: 3

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