Question

what is the most efficient way to get one directory tree level up ?
i am looking for most efficient use of string class method to
getting e:\files\report\fruits from e:\files\report\fruits\apples

Answer 1

I think you are better off just using

File f = new File("e:\\files\\report\\fruits\\apples");
String parent = f.getParent();

If you insist on using String only and assuming ‘\’ is the path separator, you can do something like this:

String s = "e:\\files\\report\\fruits\\apples";
String parent = s.substring(0, s.lastIndexOf('\\'));

But you have to beware of edge cases like there being no character ‘\’ found.