带数字的正则表达式重定向

Question

I wish to redirect a link from

http:www.testurl.com/1209/somecategory/itemid

to

http:www.testurl.com/en/uk/1209/somecategory/itemid

by using a regex expression.

At the moment I have come up with

<redirect url="~/\d/(.*)$" to="~/en/uk/0/$1/" />

which works when the number is 0.

How can I get the number entered (/d) to the second part of the link (instead of the 0)?

Thanks for your help and time

Answer 1

You should add the \\d+ (1 or more digits) to the capturing group:

url="~/(\d+/.*)$"

And replace using the $1 back-reference:

to="~/en/uk/$1/"

Thus, you do not have to hard-code digits into the replacement string.

See Use Parentheses for Grouping and Capturing and Numbered Backreferences for more details on how capturing can be used in regex.

See Regex Demo