what is the most efficient way to get one directory tree level up ? i am looking for most efficient use of string class meth开发者_运维技巧od to getting e:\files\report\fruits from e:\files\report\fruits\apples
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.
I wouldn't do this by "string bashing" because it will embed all sorts of platform dependencies on pathname syntax into your code. Instead, use the java.io.File
class.
String parent = new File("e:\files\report\fruits\apples").getParent();
or better still:
File parent = new File("e:\files\report\fruits\apples").getParentFile();
Stephen makes a valid point about platform dependency, but here's what you asked for:
String dir = "e:\\files\\report\\fruits\\apples";
String parent = dir.replaceAll("\\\\[^\\\\]+$", "");
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