Reading text files, testing @error

[JohnDoe9000]

What is the proper way to read text files line by line?

Why the following code doesn't detect end of file?

#include <FileConstants.au3>
#include <MsgBoxConstants.au3>

Local $sInputFileName = @ScriptDir & "\somefile.xml"
Local $LineCount = 0
Local $CharCount = 0

$hInFile = FileOpen($sInputFileName, $FO_READ)

While Not @error
   $sLine = FileReadLine($hInFile)
   If @error Then ExitLoop
   $LineCount += 1
   $CharCount += StringLen($sLine)
WEnd

If @error Then
   MsgBox($MB_OK + $MB_ICONERROR, "File processing", "An error occured when reading the file" & @CRLF & $sInputFileName)
Else
   MsgBox($MB_OK + $MB_ICONINFORMATION, "File processed", "File" & $sInputFileName & @CRLF & "contains " & $LineCount & " lines and " & $CharCount & " characters.")
EndIf

FileClose($hInFile)

[l3ill]

Try this

#include <FileConstants.au3>
#include <MsgBoxConstants.au3>

Local Const $sInputFileName = @ScriptDir & "\somefile.xml"
Local $LineCount = 0
Local $CharCount = 0

$hInFile = FileOpen($sInputFileName)


While 1
    $line = FileReadLine($hInFile)
    If @error = -1 Then ExitLoop
;~     MsgBox(0,'',$line)
WEnd
FileClose($hInFile)


If @error Then
   MsgBox($MB_OK + $MB_ICONERROR, "File processing", "An error occured when reading the file" & @CRLF & $sInputFileName)
Else
   MsgBox($MB_OK + $MB_ICONINFORMATION, "File processed", "File" & $sInputFileName & @CRLF & "contains " & $LineCount & " lines and " & $CharCount & " characters.")
EndIf

FileClose($hInFile)

If your are looking for line count you will need this:

_FileCountLines($file)

[l3ill]

Here it is with consolewrite & Line count 

#include <FileConstants.au3>
#include <File.au3>
#include <MsgBoxConstants.au3>

Local Const $sInputFileName = @ScriptDir & "\somefile.xml"
Local $LineCount = 0
Local $CharCount = 0

$hInFile = FileOpen($sInputFileName)


While 1
    $line = FileReadLine($hInFile)

    If @error = -1 Then ExitLoop
    $LineCount = _FileCountLines($sInputFileName)
    ConsoleWrite($line & @CRLF)
WEnd
FileClose($hInFile)


If @error Then
    MsgBox($MB_OK + $MB_ICONERROR, "File processing", "An error occured when reading the file" & @CRLF & $sInputFileName)
Else
    MsgBox($MB_OK + $MB_ICONINFORMATION, "File processed", "File" & $sInputFileName & @CRLF & "contains " & $LineCount & " lines and " & $CharCount & " characters.")
EndIf

FileClose($hInFile)

Edited March 28, 2015 by l3ill

[JohnDoe9000]

Thank you for quick reply.

I'm afraid your variant won't catch real I/O errors, both while opening the file and reading lines.

Also I want to undestand how "If @error" actually works. I expected it to be true when @error is nonzero.

And line count here is just for example.

[l3ill]

N.P.

@error reacts to the last called function and is different depending on the function (see help file)

For instance:

FileReadLine

Success: a line of text.

Failure: sets the @error flag to non-zero.

@error:

 1 = if file not opened in read mode or other error
-1 = if end-of-file is reached

In this case non zero just means your function didn't fire for some reason.

also setting If -1 exit loop makes your function end when the EOF is reached.

edit:

if you want error handling for FileOpen then insert one thereafter

Edited March 28, 2015 by l3ill

[Melba23]

Hi,

I have changed your forum display name as it was not at all suitable. When you choose a new name, please try and pick something that does not so obviously flout the ethos of the forum - which is clearly set out in the >Forum rules.

M23

[JohnDoe9000]

if you want error handling for FileOpen then insert one thereafter

 

I thought my original "While Not @error" provided one, didn't it?

Edited March 28, 2015 by JohnDoe9000

[JohnDoe9000]

Hi,

I have changed your forum display name as it was not at all suitable. When you choose a new name, please try and pick something that does not so obviously flout the ethos of the forum - which is clearly set out in the >Forum rules.

M23

Where can I duscuss this? It seems like I can't send PMs.

[water]

You have to have at least 5 or 10 posts before PM is enabled.

[Melba23]

JohnDoe9000,

I have enabled your PM facility - ready to discuss when you are.

M23

[l3ill]

 

I thought my original "While Not @error" provided one, didn't it?

Not sure... never seen (While | Wend)  used like that in AutoIT

Not to mention... it wasn't working    

However this works:

While @error = 0

Edited March 28, 2015 by l3ill

[JohnDoe9000]

It tuns out that FileOpen() doesn't set @error. I missed that point in documentation, looking at other file I/O functions that do set it.

And more, ConsoleWrite() do set it (or clear in case of success), while documentation doesn't mention this fact. Such inconsistency is really misleading.

The final code that works as intended:

#include <FileConstants.au3>
#include <MsgBoxConstants.au3>

Local $sInputFileName = @ScriptDir & "\1.txt"
Local $LineCount = 0
Local $CharCount = 0
Local $error = 0

$hInFile = FileOpen($sInputFileName, $FO_READ)

While $hInFile <> -1
   $sLine = FileReadLine($hInFile)
   $error = @error
   If $error <> 0 Then ExitLoop
   $LineCount += 1
   $CharCount += StringLen($sLine)
WEnd

If $error <> -1 Then
   MsgBox($MB_OK + $MB_ICONERROR, "File processing", "An error occured when reading the file" & @CRLF & $sInputFileName)
Else
   MsgBox($MB_OK + $MB_ICONINFORMATION, "File processed", "File" & $sInputFileName & @CRLF & "contains " & $LineCount & " lines and " & $CharCount & " characters.")
EndIf

FileClose($hInFile)

Thanks for participation.