Check if string contains \n Java

Question

How do I check if string contains \n or new line character ?

word.contains("\\n") word.contains("\n") 

Answer 1

If the string was constructed in the same program, I would recommend using this:

String newline = System.getProperty("line.separator"); boolean hasNewline = word.contains(newline); 

But if you are specced to use \n, this driver illustrates what to do:

class NewLineTest {     public static void main(String[] args) {         String hasNewline = "this has a newline\n.";         String noNewline = "this doesn't";          System.out.println(hasNewline.contains("\n"));         System.out.println(hasNewline.contains("\\n"));         System.out.println(noNewline.contains("\n"));         System.out.println(noNewline.contains("\\n"));      }  } 

Resulted in

true false false false 

In reponse to your comment:

class NewLineTest {     public static void main(String[] args) {         String word = "test\n.";         System.out.println(word.length());         System.out.println(word);         word = word.replace("\n","\n ");         System.out.println(word.length());         System.out.println(word);      }  } 

Results in

6 test . 7 test  . 

Answer 2

For portability, you really should do something like this:

public static final String NEW_LINE = System.getProperty("line.separator") . . . word.contains(NEW_LINE); 

unless you're absolutely certain that "\n" is what you want.