non - Java Regular Expression removing everything but numbers from String

java remove non alphabetic characters from string (3)

I have two strings string1 = 44.365 Online order and string2 = 0 Request Delivery. Now I would like to apply a regular expression to these strings that filters out everything but numbers so I get integers like string1 = 44365 and string2 = 0.

How can I accomplish this?

Answer #1

This is the Google Guava #CharMatcher Way.

String alphanumeric = "12ABC34def";

String digits = CharMatcher.JAVA_DIGIT.retainFrom(alphanumeric); // 1234

String letters = CharMatcher.JAVA_LETTER.retainFrom(alphanumeric); // ABCdef

If you only care to match ASCII digits, use

String digits = CharMatcher.inRange('0', '9').retainFrom(alphanumeric); // 1234

If you only care to match letters of the Latin alphabet, use

String letters = CharMatcher.inRange('a', 'z')
                         .or(inRange('A', 'Z')).retainFrom(alphanumeric); // ABCdef

Answer #2

You can make use of the ^. It considers everything apart from what you have infront of it.

So if you have [^y] its going to filter everything apart from y. In your case you would do something like

String value = string.replaceAll("[^0-9]","");

where string is a variable holding the actual text!

Answer #3
string1 = string1.replaceAll("[^0-9]", "");
string2 = string2.replaceAll("[^0-9]", "");