Identify valid characters of a character array

Question

I am receiving a character array where it has valid and invalid characters. I need to only retrieve the characters that are valid. How can I do this ?

char[]ch = str.toCharacterArray();
for(int i=0;i<ch.length.i++){
    if(!Character.isLetter(ch[i]))
         system.out.println("not valid");
    else  
        system.out.println("valid");
}

I don't think the above code works because I get invalid for all the valid and invalid characters in the character array.

by meaning characters I am expecting all alphanumeric and special characters

Note: I am getting values from the server, therefore the character array contains valid and invalid characters.

You start off by talking about a byte array but then you talk about characters, and your code has a string. Which is it? And what sort of "invalid characters" do you mean? — Jon Skeet
– Jon Skeet, Commented Jan 30, 2013 at 8:17
I don't see a good reason why the server should be giving you invalid characters unless you are getting binary data which happens to contain some text and you don't know what to do with the rest of the content. There are is only two characters defined as invalid but I suspect you want printable characters. — Peter Lawrey
– Peter Lawrey, Commented Jan 30, 2013 at 8:18
I have edited the post, Yes i want to have printable characters. — Sharon Watinsan
– Sharon Watinsan, Commented Jan 30, 2013 at 8:19
If the server is not broken, then it's sending you "correct" data in some format. I can't imagine a case where plucking the printable characters out of the data is preferably to truly understanding the format and extracting what you know must be the data you care about. — Duncan Jones
– Duncan Jones, Commented Jan 30, 2013 at 8:27
So you just want letter/numbers, and remove all spaces and other symbols or control chars? — Johannes
– Johannes, Commented Jan 30, 2013 at 8:32

Bimalesh Jha · Accepted Answer · 2013-01-30 09:09:58Z

1

try following method:

// assume input is not too large string
public static String extractPrintableChars(final String input) {
    String out = input;
    if(input != null) {
        char[] charArr = input.toCharArray();
        StringBuilder sb = new StringBuilder();  
        for (char ch : charArr) {
            if(Character.isDefined(ch) && !Character.isISOControl(ch)) {
                sb.append(ch);
            }
        }
        out = sb.toString();
    }
    return out;
}

answered Jan 30, 2013 at 9:09

Bimalesh Jha

1,5009 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Punith Raj · Accepted Answer · 2013-01-30 08:32:20Z

0

Have a look into Matcher class available in java. I don't think it to be wise to loop over all the characters until there is a max Cap for it.

/[^0-9]+/g, ''

with above regEx it will wipe out all the charecters other then numeric with noting. Modify it as per your need.

regards Punith

answered Jan 30, 2013 at 8:32

Punith Raj

2,2236 gold badges28 silver badges48 bronze badges

Collectives™ on Stack Overflow

Identify valid characters of a character array

2 Answers 2

Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Linked

Related