Counting the files in a folder

nikolaj

I am not very good at managing data.

I am saving some coordinates, that i need to load in a number of .txt files, in my sketch's Data folder, it looks a little like this:

How many .txt folders there are in different each folder is not fixed, the one on the image has only 2 files i that shall be loaded, but some other has 3, 4 or 5. (and possiply some will have even more, but what i know for sure is that none will have only one)

To load all the files, i must know how many files there are. As you can see, my solution was to add a file named »steps.txt« containing only one int: the number of files to be loaded. In the case shown on the picture, 2:

int numberOfFiles = int(loadStrings("data/folderName/steps")[0]);

But, it would be much easier, if there was a way to count the number of files in a folder, something like:

int numberOfFiles = getFileCount("data/folderName");

And i am also very sure that there is a way to do that (a library or something like that), i just don't know how.

GoToLoop

You're gonna need a FilenameFilter instance used as argument for File's list() method:

• https://docs.oracle.com/javase/8/docs/api/java/io/FilenameFilter.html
• https://docs.oracle.com/javase/8/docs/api/java/io/File.html#list-java.io.FilenameFilter-

You can check out an example of it in this post link:
http://forum.processing.org/two/discussion/6677/splitting-a-text-file-using-crlf-and-parsing-file-

Here's a custom FilenameFilter that would work for ya:

import java.io.FilenameFilter;

static final FilenameFilter FILTER = new FilenameFilter() {
  static final String NAME = "step", EXT = ".txt";

  @ Override boolean accept(File path, String name) {
    return name.startsWith(NAME) && name.endsWith(EXT);
  }
};

And a sample on how to use File's list() method:

File f = dataFile("folderName");
String[] names = f.list(FILTER);
printArray(names);

Chrisir

ah, and then just names.length ?

nikolaj

Thanks, now it works.

Not that having a .txt file containing the number of files in the directory as an int didn't work, but this looks better, both in the code, and in my data folder

GoToLoop

Oh, forgotten to tell if we're sure all of the files within a folder is what we want, FilenameFilter is unnecessary. 8-|
A simple list() w/o any arguments is pretty enough: *-:)
https://docs.oracle.com/javase/8/docs/api/java/io/File.html#list--

nikolaj

I removed the FilenameFilter, and used only file.list()... and it always returned a number 1 greater than the actual number of files in the.

It turns out that every single folder (even empty ones) contains a file called ".DS_store" (that Apple for some reason doesn't think i want to know is there)

i suptract one from the total number of files, and it works perfectly.

GoToLoop

I subtract 1 from the total # of files, and it works perfectly.

Problem is that your sketch will only work correctly in MacOS w/o FilenameFilter I'm afraid! :-SS

PhiLho

Would be better to exclude all files whose name starts with a dot...

GoToLoop

Would be better to exclude all files whose name starts with a dot...

I don't have a Mac. Actually I'm not using any Windows, just Linux now! <):)
But I guess the same way that Windows spreads those odious "Thumbs.db" system files in every folder w/ images in it, unless we disable it but we still got to delete them manually, Macs much probably will recreate those cretin ".DS_store" as well! X(

Chrisir

I have a question on that

when I want to have jpg and JPG and bmp

do I have to use , or ; to separate them ?

both won't work

static final String NAME = "", EXT = ".jpg;.JPG";

I'm on Win 7

thanks!

GoToLoop

This is old and somehow I've missed it. :-\"
Nonetheless @Chrisir, If it happens to be mixed lower & upper case letters, call toLowerCase() before endsWith() & startsWith(): :P

import java.io.FilenameFilter;

static final FilenameFilter FILTER = new FilenameFilter() {
  static final String NAME = "step", EXT = ".txt";

  @ Override boolean accept(File path, String name) {
    name = name.toLowerCase();
    return name.startsWith(NAME) && name.endsWith(EXT);
  }
};

Chrisir

thank you!

akenaton

@nikolaj== i had the same problem with .DS invisible file (apple) and it is more vicious than you say because this file is not always present: try with onyx you can verify e.g that it does not exist when you create a folder and appears only with some conditions (copy etc); what is sure is that when present it is always the first one in the folder: so i have made a little method which looks at the first element && if equals .DS or startsWith() skips this file: so you dont have too look the other files in the folder...