HMR to grab digits of uri-user and replace it with another initial digit

Hi Fellows,

I hope you are ok.

I would like if someone can help with some tips to achieve grab some values of a uri-user values when start for example with "1" example "1xyz" and after check that start with 1 then take the rest of the values and replace these with another initial digit.

By now I was just achieved check when start with "1" and after that, I did a test to replace with another value. But like a say above, I am trying to grab the rest of the values and replace with another intial value.

I will follow trying all that I can get to grab the other digits after "1" stored and used these values to replace the new one.