String Array Manipulation

[thomasjbs]

Anyone know how to initialize an array without sizing it first?

// This works - returns a list of files and directories
File dlist = new File("C:\\");
String[] files = dlist.list();

// To get directories only:
for (int x=0;x<files.length;x++) {
File filename = new File("C:\\"+files[x]);
if ( filename.isDirectory()) {
dirs[cnt++] = filename.getParent() +
filename.getName();
}
}

But how do I initialize dirs?

// This results in uninitialized variable error
String[] dirs;

// This results in an array that is too large (causes empty lines when
sending to JComboBox)
String[] dirs = new String[20];

 

[Ingo R. Homann]

Hi,

Take a look at the classes ArrayList<String> or LinkedList<String>.

Hth,
Ingo

 

[Dieter Lamberty]

Anyone know how to initialize an array without sizing it first?

// This works - returns a list of files and directories
File dlist = new File("C:\\");
String[] files = dlist.list();

// To get directories only:
for (int x=0;x<files.length;x++) {
File filename = new File("C:\\"+files[x]);
if ( filename.isDirectory()) {
dirs[cnt++] = filename.getParent() +
filename.getName();
}
}

But how do I initialize dirs?

// This results in uninitialized variable error
String[] dirs;

// This results in an array that is too large (causes empty lines when
sending to JComboBox)
String[] dirs = new String[20];

Hi

Beside the way Ingo mentioned you may use the method
listFiles(FileFilter) instead of list(). With that you will get an Array
of all Directories (as File Objects) and can use these.

File[] files = dlist.listFiles(new FileFilter() {
public boolean accept(File f) {
return f.isDirectory();
}
} );

Hope that helps
Dieter