Regex to validate that every digit is different from each other-CodePudding

I have to validate strings with specific conditions using a regex statement. The condition is that every digit is different from each other. So, 123 works but not 112 or 131.

So, I wrote a statement which filters a string according to the condition and prints true once a string fullfies everything, however it only seems to print "true" altough some strings do not meet the condition.

public class MyClass {
    public static void main(String args[]) {
        
    String[] value = {"123","951","121","355","110"};
    
    for (String s : value){
        System.out.println("\""   s   "\""   " -> "   validate(s));
    }
}
    
    public static boolean validate(String s){
        return s.matches("([0-9])(?!\1)[0-9](?!\1)[0-9]");
    }
}

CodePudding user response：

@Vinz's answer is perfect, but if you insist on using regex, then you can use:

public static boolean validate(String s) {
    return s.matches("(?!.*(.).*\\1)[0-9] ");
}

CodePudding user response：

You don't need to use regex for that. You can simply count the number of unique characters in the String and compare it to the length like so:

public static boolean validate(String s) {
    return s.chars().distinct().count() == s.length();
}