Question

I am attempting to use java scanner with the following set of delimiters & = ~ ^ (ampersand, equals, tilde, caret) by using method useDelimiter("&|=|~|^");.

All the delimiters work OK apart from ^ which is ignored: why is that?

I cannot see why in the Scanner documentation.

Answer 1

You need to escape ^, like this: useDelimiter("&|=|~|\\^"). That’s because ^ is a meta-character in regular expressions, and the String parameter of useDelimiter() ends up being compiled to a regex Pattern.

Equivalently, you could write the delimiter like this, in this case there’s no need to escape the ^: useDelimiter("[&=~^]")