CODEWITHSUNDEEP
java
Muratcan
Muratcan

Reputation: 235

Java StringBuilder Return unwanted characters

I have a StringBuilder and i want to get characters except numbers and following characters(+, -, *, /).

I wrote this code.

   StringBuilder sb = new StringBuilder(" a  + 5 v 5 + 6 + 7");
   String nieuw = trimOriginal(sb);
   System.out.println(nieuw);
   if(nieuw.matches("[a-zA-Z ]*\\d+.*")){
       System.out.println(nieuw);   

   }else {
       System.out.println("contains illegal charters");
   }

public static String trimOriginal(StringBuilder sb) {
        return sb.toString().trim();
    }

i want print hier also a and v.

can somebody help me

Upvotes: 0

Views: 100

Answers (2)

T.G
T.G

Reputation: 1921

public static void main(String[] args) {
    StringBuilder sb = new StringBuilder(" a  + 5 v 5 + 6 + 7");
    String nieuw = trimOriginal(sb);
    System.out.println(nieuw);
    if (nieuw.matches("[^0-9+/*-]+")) {
        System.out.println(nieuw);

    } else {
        System.out.println("contains illegal charters");
    }
}

public static String trimOriginal(StringBuilder sb) {
    String buff = sb.toString();
    String[] split = buff.split("[0-9+/*-]+");
    StringBuilder b = new StringBuilder();
    for (String s : split) {
        b.append(s);
    }
    return b.toString().trim();
}

OUTPUT

a    v
a    v

Upvotes: 2

npinti
npinti

Reputation: 52185

The problem with matches is that it will attempt to match the entire string. Changing it to something like so should work:

    StringBuilder sb = new StringBuilder(" a  + 5 v 5 + 6 + 7");
    Pattern p = Pattern.compile("([^0-9 +*/-])");
    Matcher m = p.matcher(sb.toString());
    while(m.find())
    {
        System.out.println(m.group(1));
    }

Yields: a v.

Upvotes: 1

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