Regex.Replace: How to use $groups followed by numbers

Question

With Regex::Replace we can use $1, $2, ... to match corresponding groups. But how can I use $1 followed by number. E.g. to replace 6 with 678?

 Regex::Replace(text, "(6)", '$178');

Answer 1

It seems I can use $`

Regex::Replace(text, "(6)", '$1$`78');

Answer 2

You need to use the alternate syntax:

Regex::Replace(text, "(6)", "${1}78");

Answer 3

You can use backreferences to capture a named group and replace that named group with whatever you want. view this link