Remove all control characters except \n & \r

[Srikanth Madasu]

I have a requirement of removing all the control characters from a string except CarriageReturn (CR) and LineFeed (LF).

I know how to remove all the control characters:

		String szStr = "A\tThis is super duper \\Q \tbig line\rhello\n this is new line.";
		System.out.println(szStr);
		Pattern p = Pattern.compile("\\p{Cntrl}");
		Matcher m = p.matcher("");
		m.reset(szStr);
		String result = m.replaceAll(" ");
		System.out.println(result);

But i now want retain CR & LF and remove all other control characters.
Any help is much appreciated.

Thanks in advance.

[Rob Spoor]

The API of Pattern already tells you how to do this - if you know where to look. It's in the "Character classes" section: [a-z&&[^bc]]. In this case, it's [\\p{Cntrl}&&[^\r\n]]

Keep in mind that the results are... odd. The \r only returns the cursor position to the start of the same line on Windows, so this is the output:

hello   This is super duper \Q  big line
 this is new line.
hellos is super duper \Q  big line
 this is new line.

As you see, the "hello" is overwriting the start of the line. At first, it will overwrite the "A" and part of the tab. After the pattern replacing, it will replace "A Thi".