Question

I have a string like

“The brown fox @jumped@ over the @fence@”

, and I wish to replace all substrings between two '@' by ‘kicked‘ i.e. the final output should be :

“The brown fox kicked over the kicked”

I wrote the following but can’t figure out the mistake :

string.replaceAll("^@.*@$", "kicked");

Answer 1

You should not use anchor elements ^ and $. They mean the beginning and the end of the entire input, not the beginning and the ending of the word. You should also replace the dot . with [^@] (meaning “anything but @“) to make your expression more efficient.

string.replaceAll("@[^@]*@", "kicked");

If you would like to avoid replacing tagged elements inside a word, e.g. if you want to preserve he@ll@o as is, rather than making it hekikkedo, you can put in markers of word boundaries \b on both ends of the expression:

string.replaceAll("\\b@[^@]*@\\b", "kicked");