Re: Math.random()
maya wrote:
Jeff Higgins wrote:
import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.Collections;
public class ShuffleImages {
public static void main(String[] args) {
ArrayList photos = new ArrayList();
File directory = new File(System.getProperty("user.dir"));
String[] textFileNames = directory.list(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith(".jpg") || name.endsWith(".JPG");
}
});
for (int i = 0; i < textFileNames.length; i++) {
photos.add(new File(textFileNames[i]));
}
Collections.shuffle(photos);
}
}
thank you very much.. I have incorporated this code into my class to
rename files, it now looks thus, and get no compile or runtime errors,
but it's still not doing it at random, i.e., what I want:
if I have: DSC_0184.JPG, DSC_0185.JPG, DSC_0186.JPG, DSC_0187.JPG,
DSC_0188.JPG, DSC_0189.JPG, DSC_0190.JPG, DSC_0191.JPG, DSC_0192.JPG,
I want, for example: 8th img in this list to be called 1.jpg, 4nd img to
be called 3.jpg, sixth image to be called 10.jpg, etc.. so once they
are renamed they are ordered at random vis-a-vis orig order.. what I
have now after incorporating yr code:
---------------
public class renameRandom {
public static void main(String[] args) {
int posDot;
String _temp = "";
String no = "";
File directory = new File(System.getProperty("user.dir"));
String[] textFileNames = directory.list(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.endsWith(".jpg") || name.endsWith( ".JPG");
}
});
ArrayList photos = new ArrayList();
for (int i=0; i < textFileNames.length; i++) {
photos.add(new File(textFileNames[i]));
}
Collections.shuffle(photos, new Random());
for (int i = 0; i < textFileNames.length; ++i) {
File oldFile = new File(textFileNames[i]);
posDot = textFileNames[i].indexOf(".");
_temp = textFileNames[i].substring(0,posDot);
File newFile = new File(i+1 + ".jpg");
oldFile.renameTo(newFile);
}
}
}
still trying to incorporate random "feature" into this renaming class..
maybe I need to modify this line?
File newFile = new File(i+1 + ".jpg");
so it when renaming imgs it goes thru the imgs at random instead of how
they are ordered originally??
thank you very much..
so I figured after shuffling them I need to put them in an array.. yes??
so I now have:
ArrayList photos = new ArrayList();
for (int i=0; i < textFileNames.length; i++) {
photos.add(new File(textFileNames[i]));
}
Collections.shuffle(photos, new Random());
String[] photosArr = new String[photos.size()];
photos.toArray(photosArr); // runtime error on this line..
for (int i = 0; i < photosArr.length; ++i) {
File oldFile = new File(photosArr[i]);
posDot = photosArr[i].indexOf(".");
_temp = photosArr[i].substring(0,posDot);
File newFile = new File(i+1 + ".jpg");
oldFile.renameTo(newFile);
}
it compiles fine, but get a runtime error, thus:
Exception in thread "main" java.lang.ArrayStoreException
at java.lang.System.arraycopy(Native Method
at java.util.ArrayList.toArray(Unknown Sour
at renameRandom.main(renameRandom.java:40)
line 40 is: photos.toArray(photosArr);
( I looked up ArrayList in docs, it looks like it can be converted to an
array in same way as Vector can, and I have done it w/Vector before..)
thank you..