Java regular expression to remove all non alphanumeric characters EXCEPT spaces

Question

I\'m trying to write a regular expression in Java which removes all non-alphanumeric characters from a paragraph, except the spaces between the words.

This is the co

Answer 1

You need to escape the \ so that the regular expression recognizes \s :

paragraphInformation = paragraphInformation.replaceAll("[^a-zA-Z0-9\\s]", "");

Answer 2

Generally whenever you see that error, it means you only have a single backslash where you need two:

paragraphInformation = paragraphInformation.replaceAll("[^a-zA-Z0-9\\s]", "");

Answer 3

You need to double-escape the \ character: "[^a-zA-Z0-9\\s]"

Java will interpret \s as a Java String escape character, which is indeed an invalid Java escape. By writing \\, you escape the \ character, essentially sending a single \ character to the regex. This \ then becomes part of the regex escape character \s.

Answer 4

Please take a look at this site, you can test Java Regex online and get wellformatted regex string patterns back:

http://www.regexplanet.com/advanced/java/index.html

Answer 5

Victoria, you must write \\s not \s here.