How to remove all special characters from a string in java?

Question

I want to remove all special characters from a string,i tried many options which were given in stackoverflow, but none of them work for me.

here is my code :

public class convert {

    public static void main(String[] args) {
        try {    
            List<List<String>> outerList = new ArrayList<List<String>>();
            outerList.add(new ArrayList<String>(asList("11-","2")));
            outerList.add(new ArrayList<String>(asList("(2^","1")));
            outerList.add(new ArrayList<String>(asList("11","3)")));    

            int i,j;
            for(i=0;i<outerList.size();i++){    
                    for(j=0;j<outerList.get(0).size();j++){    
                            outerList.get(i).get(j).replaceAll("[^\\w\\s]", "");
                            if(outerList.get(i).get(j).matches("-?\\d+"){
                               continue;
                            }else{
                               System.out.println("special characters not removed");
                               System.exit(0);
                            }
                   }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

What are the special characters? Not alphanumeric ones? Command ones? That of in range [32..255] - ASCII nut not command? — Dmitry Bychenko, Sep 11 '14 at 10:03

score 5 · Accepted Answer · answered Sep 11 '14 at 10:16

5

The (simple) error is that s.replaceAll(...) does not change s but yields a new changed string:

String s = outerList.get(i).get(j).replaceAll("[^\\w\\s]", "");
outerList.get(i).set(j, s);

answered Sep 11 '14 at 10:16

Joop Eggen

107,315
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score 1 · Answer 2 · edited May 23 '17 at 12:08

1

in the case of not alphanumeric you can use

String value = "hello@() world";
value = value.replaceAll("[^A-Za-z0-9]", "");
System.out.println(value) // => helloworld

something similar has already been asked here

edited May 23 '17 at 12:08

Community

1
1

answered Sep 11 '14 at 10:04

Enermis

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Note that you can use `\p{Alnum}` instead of `A-Za-z0-9`. – Florent Bayle Sep 11 '14 at 10:08
@AnoopDobhal Don't forget that `String` are immutable, so you have to assign the value back to the `String`: `value = value.replaceAll(...)` – Florent Bayle Sep 11 '14 at 10:10
@Enermis : OP don;t want examples like you provide, he want the hint / answer that in his code where he's wrong.. – user3145373 ツ Sep 11 '14 at 10:13

score -3 · Answer 3 · answered Sep 11 '14 at 10:17

-3

Use StringUtils at Apache Commons Lang (http://commons.apache.org/proper/commons-lang/):

http://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/StringUtils.html

answered Sep 11 '14 at 10:17

eruiz

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6

Which method does this? – JustinKSU Apr 17 '17 at 21:55
2

I think that the author of the post forgot to mention the use the method stripAccents of StringUtils – thiagoms83 Jan 15 '20 at 17:24

How to remove all special characters from a string in java?

3 Answers3