Question

How would I replace all that is not stored in the variable guess in the current Pattern with a “-“? The guess will change with different method calls. I want to replace anything that is not the char guess(in this case => ‘e’) with a “-“.

String word = "ally";
char guess = 'e';
String currentPattern = word.replaceAll("[^guess]", "-");

Obviously, this does not work.

Answer 1

You almost have it. Use String concatenation:

String currentPattern = word.replaceAll("[^" + guess + "]", "-");

This approach only works if you don’t have regex metacharacters within guess, which need to be escaped within character classes. Otherwise a PatternSyntaxException will be thrown.

This question shows that in your case, where you only add a char to your character class, a PatternSyntaxException won’t happen even if you don’t escape anything.