Regex To Remove Spaces Between Numbers Only

I need to remove the spaces between numbers only, so that a string like this: 'Hello 111 222 333 World!' becomes 'Hello 111222333 World!' I've tried this: message = message.repla

Solution 1:

You can use this lookaround based regex:

String repl ="Hello 111 222 333 World!".replaceAll("(?<=\\d) +(?=\\d)", "");
 //=> Hello 111222333 World!

This regex "(?<=\\d) +(?=\\d)" makes sure to match space that are preceded and followed by a digit.

Solution 2:

How about:

message = "Hello 111 222 333 World!".replaceAll("(\\d)\\s(\\d)", "$1$2");

Gives:

"Hello 111222333 World!"