Question

I want to replace char ‘&’ if it’s not followed by ‘#’. For example in this string "& hello &# world!" I’d want to select only the first ‘&’.

So far I came up with this regex:

&[^#]

However, this selects 2 characters, whereas I want to only select the ampersand character.

Any help from RegExp Gurus would be appreciated.

BTW. It may be important: I want to use it in java replaceAll().

Many thanks,
Damo

Answer 1

Using negative lookahead:

System.out.println("& hello &# world!&".replaceAll("&(?!#)", "&"));

Prints:

& hello &# world!&