Regex expression the . operator in Java

Question

I am searching for a String in a file that has any non numeric character and no dollar sign in it. when i use

[\\D&&[^$]]+ 

it works but if i use

[.&&[^$]]+

the code doesn't work.Can anyone explain the reason.

Answer 1

Why

The . dot in a char class [] means exactly a dot, not any character as it works outside character classes.

Solution

What you're looking for is a negated character class:

RegEx: [^0-9$] live demo

Answer 2

Inside the character-class [] the . char is not a wildcard, but an actual dot. You don't need to intersect the dot with your "not" char, you can simply write [^$0-9 ]+ (which is however not what you are looking for I guess).