How to check if a file exists

Share icon

Wed, 03/18/2009 - 04:04 pm

I'm looking for a simple way to check to see if a file exists, but without actually opening up the file and taking the time to read its contents.

Maybe someone can suggest a smarter way to solve my problem: Our data folders are organized such that I have a bunch of files with names like

a1.txt, a2.txt... a122.txt, b1.txt, b2.txt, b3.txt... b235.txt, c1.txt...

I'd like to process all of the "a" files at once. Right now I have to manually enter the number of files to run my processing loop on. I'd like to automate that. I tried using IndexedFile but I couldn't figure out how to make it work for files that weren't just numbered as 001.txt, 002.txt, 003.txt...

Alternatively, is there a way to keep LoadWave from complaining with a dialog box if it doesn't find the file it's looking for?
wholmgren wrote:
I'm looking for a simple way to check to see if a file exists, but without actually opening up the file and taking the time to read its contents.


For that, you are better off using GetFileFolderInfo with the /Z=1 flag. You can inspect the value of V_Flag to determine whether the file or folder was found, and the value of V_isFile if you need to be sure it's actually a file and not a folder.


wholmgren wrote:

Maybe someone can suggest a smarter way to solve my problem: Our data folders are organized such that I have a bunch of files with names like

a1.txt, a2.txt... a122.txt, b1.txt, b2.txt, b3.txt... b235.txt, c1.txt...

I'd like to process all of the "a" files at once. Right now I have to manually enter the number of files to run my processing loop on. I'd like to automate that. I tried using IndexedFile but I couldn't figure out how to make it work for files that weren't just numbered as 001.txt, 002.txt, 003.txt...

Alternatively, is there a way to keep LoadWave from complaining with a dialog box if it doesn't find the file it's looking for?


There are quite a few ways you could approach this. The one I thought of first was to use the following snippet. Just put it in a function somewhere and it should work (though I haven't tested it).

    // Get a list containing all text files in the
    // specified symbolic path.
    String fileList = IndexedFile(myPath, -1, ".txt")
   
    // Filter the list of files to include
    // only files that start with the letter "a".
    fileList = ListMatch(fileList, "a*", ";")
   
    // Do something to each of these files
    Variable n, numFiles = ItemsInList(fileList, ";")
    For (n=0; n<numFiles; n+=1)
        // do your processing here 
    EndFor

March 18, 2009 at 05:19 pm - Permalink