RegEx reconstruction with replace with groups

Question

We are doing URL rewrite and user can type url as

 somesite.com/category6/page.aspx

Now we want to rewrite the url as

 somesite.com/6/category/page.aspx.

We already have bunch of regex for url rewrite however replace string is static, we wanted follow the same pattern and not to customize for this particular one.

Answer 1

rewrite rule :

(category)([0-9]+)(/?.*)

parsing :

{R:0} category6/page.aspx

{R:1} category

{R:2} 6

{R:3} /page.aspx

using the rules :

{R:2}/{R:1}{R:3}