Removing desired character from a String (From a String or char[])

Question

Removing desired character from a String (From a String or char[])

I've searched around the Java sections but haven't found an adequate answer. I'm testing out some basic (extremely basic) object obscuring for serialization just to get the feel of it.

---

To de-obscure my object I need to remove the added character that I've put on my object.

Eg

Profile name is original "John"

I then turn it into, "#J/oH@n"

I would then need to reverse the latter into the original by removing the symbols. However I couldn't find a suitable/efficient way of doing so.

---

Please do keep in mind that my list of symbols could be saved in char[] or just one String like so:

char[] obcChars = {'#', ';', '"', '¬', '¦', '+', ';'
        , '/', '.', '^', '&', '$', '*'
        , '[', '@', '-', '~', ':'};

String s = new String(obcChars);

Whichever method you need to use to facilitate your answer is fine by me! I'd also like to thank you in advance.

Answer 1

To remove characters at an index from a String you have to use a StringBuilder which is a mutable version of a String (you can change StringBuilders)

String s = "Hello World";
StringBuilder sb = new StringBuilder(s);
sb.removeCharAt(sb.indexOf('e'));
s = sb.toString();
System.out.println(s); // Prints Hllo World

Answer 2

You can use regex:

    String obcChars = "[^a-zA-Z]";
    String word = "#J/oH@n";
    word = word.replaceAll(obcChars, "");
    System.out.println("word = " + word);

OUTPUT

word = JoHn

Answer 3

You can create a regular expression which contains the characters you want to remove:

    char[] obcChars = {'#', ';', '"', '¬', '¦', '+', ';'
            , '/', '.', '^', '&', '$', '*'
            , '[', '@', '-', '~', ':'};
    StringBuilder sb = new StringBuilder();
    sb.append(obcChars[0]);
    for (int i=1; i<obcChars.length; i++) {
        sb.append("|\\");
        sb.append(obcChars[i]);
    }
    // sb now contains the regex #|\;|\"|\¬|\¦|\+|\;|\/|\.|\^|\&|\$|\*|\[|\@|\-|\~|\:

Then just use the String#replaceAll() method to take them out of your input string:

    String oName = "#J/oH@n";
    System.out.println(oName.replaceAll(sb.toString(), "")); // prints JoHn

Note

This will be useful if you know which characters you want to remove, and they are a limited subset of non-alpha. If you just want to trim out all non-letters, see @alfasin's answer for a much simpler solution to that problem.