Question

I’m trying to replace the last dot in a String using a regular expression.

Let’s say I have the following String:

String string = "hello.world.how.are.you!";

I want to replace the last dot with an exclamation mark such that the result is:

"hello.world.how.are!you!"

I have tried various expressions using the method String.replaceAll(String, String) without any luck.

Answer 1

One way would be:

string = string.replaceAll("^(.*)\\.(.*)$","$1!$2");

Alternatively you can use negative lookahead as:

string = string.replaceAll("\\.(?!.*\\.)","!");

Regex in Action