Java Regular Expression removing everything but numbers from String

Question

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?

DaMainBoss · Accepted Answer · 2011-08-23T04:08:32.737

75

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!

edited Aug 23 '11 at 04:08

answered Jul 30 '11 at 14:07

DaMainBoss

1,985
1
18
25

`\D` would 67% shorter as a pattern. ;) – tchrist Aug 23 '11 at 04:12
Yes but far less efficient. – DaMainBoss May 29 '13 at 18:15
@DaMainBoss how to include negative numbers also? I mean, I have to replace everything that is not a positive/negative number with an empty space. How to do that? – Pankaj Singhal Sep 06 '15 at 09:07
@PankajSinghal negative numbers start with `-` so something like `[^-?0-9]` should do the trick. `-?` there tells the regex engine to match `-` if it exists(0 or none). – DaMainBoss Sep 10 '15 at 08:15

score 27 · Answer 2 · edited Jan 23 '14 at 15:48

27

String clean1 = string1.replaceAll("[^0-9]", "");

or

String clean2 = string2.replaceAll("[^\\d]", "");

Where \d is a shortcut to [0-9] character class, or

String clean3 = string1.replaceAll("\\D", "");

Where \D is a negation of the \d class (which means [^0-9])

edited Jan 23 '14 at 15:48

David Chouinard

5,676
8
41
60

answered Jul 30 '11 at 14:02

om-nom-nom

61,565
12
180
225

score 10 · Answer 3 · answered Jul 30 '11 at 14:01

10

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

answered Jul 30 '11 at 14:01

JK.

5,086
1
26
26

Kerem Baydoğan · Answer 4 · 2015-10-01T13:22:56.600

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

Java Regular Expression removing everything but numbers from String

4 Answers4

Linked