Is there an easy way to check if File.txt exists?

[Nituvious]

Is there any easy way for us to check if for example, FileA.txt exist, and if it doesn't then use FileB.txt?
I have been looking through the FileSystem and File reference in the help file but I don't seem to find anything relevant. I probably am not looking hard enough though.

[Nituvious]

Sorry for the double post, I just used ReadFile(#,String$) and I got what I needed. Does anyone know ReadFile is safe to use with executables?

[rsts]

If readFile(0,"fileA.txt")
do fileA stuff
else
If readFile(0,"fileB.txt")
do fileB stuff
else
No file B either
EndIF
EndIF

something like this?

cheers

[Nituvious]

If readFile(0,"fileA.txt")
do fileA stuff
else
If readFile(0,"fileB.txt")
do fileB stuff
else
No file B either
EndIF
EndIF

something like this?

cheers

Thanks but is this safe to use with an executable?

[rsts]

If readFile(0,"fileA.txt")
do fileA stuff
else
If readFile(0,"fileB.txt")
do fileB stuff
else
No file B either
EndIF
EndIF

something like this?

cheers

Thanks but is this safe to use with an executable?

Since the description is "Open an existing file for read-only operations", it should be. It doesn't do any actual reading.

cheers

[Fangbeast]

What's wrong with the FileSize command? A value of -1 will tell you that the file does not exist and you do not need to open it first.

From the manual

Code: Select all

Syntax

Result.q = FileSize(Filename$)

Description

Returns the size of the specified file. 

Special 'Result' values: 
  -1: File not found.
  -2: File is a directory.

Supported OS 

All

[Michael Vogel]

Not tested, but should work...

Code: Select all

Procedure.l OpenFirstFile(n,a.s,b.s="")
	If FileSize(a)>=0
		ReadFile(n,a)
		ProcedureReturn 1
	ElseIf FileSize(b)>=0
		ReadFile(n,b)
		ProcedureReturn 2
	Else
		ProcedureReturn 0
	EndIf
EndProcedure

If OpenFirstFile(7,"TextA.txt","TextB.txt")

	Debug ReadString(7)
	CloseFile(7)
EndIf

[Fred]

If you want to use ReadFile(), no need to check it before, it's double check. Also, ALWAYS check the return of ReadFile, it could exists but be locked by an application.

[Michael Vogel]

Depending if the first readable file should be opened or the first existent should be tried to open there are some variants possible ...

Code: Select all

Procedure.l OpenFirstFile(n,a.s,b.s="")

	If ReadFile(n,a)
		ProcedureReturn 1
	ElseIf ReadFile(n,b)
		ProcedureReturn 2
	Else
		ProcedureReturn 0
	EndIf

EndProcedure

Code: Select all

Procedure.l OpenFirstFile(n,a.s,b.s="")

	If FileSize(a)>=0
		If ReadFile(n,a)
			ProcedureReturn 1
		EndIf

	ElseIf FileSize(b)>=0
		If ReadFile(n,b)
			ProcedureReturn 2
		EndIf
	EndIf
	
	ProcedureReturn 0
	
EndProcedure

[helpy]

Depending if the first readable file should be opened or the first existent should be tried to open there are some variants possible ...

With these functions you can not use #PB_Any, because you would need the result of ReadFile() to Close the opened file.

[Michael Vogel]

Depending if the first readable file should be opened or the first existent should be tried to open there are some variants possible ...

With these functions you can not use #PB_Any, because you would need the result of ReadFile() to Close the opened file.

Code: Select all

Procedure.l OpenFirstFile(n,a.s,b.s="")

	Protected Result

	Result=ReadFile(n,a)

	If Result
		ProcedureReturn Result
	Else
		Result=ReadFile(n,b)
	EndIf

	ProcedureReturn Result

EndProcedure

[Nituvious]

ReadFile() does the trick! I needed someway of checking if one of two files existed, if one did it would set the appropriate file path. Thank you guys for all of the help!

[Fred]

To just check the file existance, FileSize() is faster (hey Fang !).

[SFSxOI]

Code: Select all

If FileSize("C:\some_file.txt") <> -1 And FileSize("C:\some_file.txt") <> -2
MessageRequester("Information", "Path set", #PB_MessageRequester_Ok)
;set path here
Else
MessageRequester("Information", "file not found", #PB_MessageRequester_Ok)
; file does not exist
EndIf

[helpy]

Instead of:

Code: Select all

If FileSize("C:\some_file.txt") <> -1 And FileSize("C:\some_file.txt") <> -2
  ;(...)
EndIf

...you can write:

Code: Select all

If FileSize("C:\some_file.txt") > -1
  ;(...)
EndIf

...or:

Code: Select all

If FileSize("C:\some_file.txt") >= 0
  ;(...)
EndIf

... otherwise FileSize() is called twice, if the file exists