Ignoring spaces and non-alphanumeric characters

Question

I need some help with this program im working on. It's testing to see whether words are palindromes or not. The trouble is, i need to make the program ignore spaces and puncuation. Does anyone know of a command to do this, or a command where i can list all the common types of puncuation and get the program to ignore them.
Thanks

Answer 1

you can use regular expressions (regex) for this. I'm not very experienced with regex (though I admit I should become familiar with it ;)), so for more information check out Sun's regex tutorial and regular-expressions.info.
if you're not interested in regex (or if you don't have access to a 1.4+ SDK), you can just use ASCII filtering to achieve this (see this ASCII table for basic ASCII values). Basically, you're only going to accept A-Z and 0-9 characters (if I understand your question correctly). This means the only ASCII values you want to accept is 48-57, 65-90, and 97-122. You can use a simple boolean method to check if a character is valid. Something like this should work:
public boolean valid(char c) {
     int x = (int)c; // ascii value of c
     return ((x >= 48 && x <= 57) || (x >= 65 && x <= 90) || (x >= 97 && x <= 122));
}Use this method on every character of the String you want to process. So to validate an entire String you can use a method like this:
public boolean valid(String s) {
     for (int j = 0;j < s.length();j++) {
          if (!valid(s.charAt(j))) {
               return false;
     return true;
}Beware though that this is considerably slower than using regular expressions. Also I didn't compile this example so there might be a small mistake you'll have to fix.