Question

What does this regex do? i know it replaces the filename (but not extension)

    Regex r = new Regex('(?<!\\.[0-9a-z]*)[0-9]');     return r.Replace(sz, '#'); 

How do i make it only repeat 5 times? to make it convert ‘1111111111.000’ to ‘11111#####.000’ ?

Answer 1

I havent’ tried this but Have tried it, works: how about changing the general pattern to use a positive lookahead instead? That way, it should work:

[0-9a-z](?=[0-9a-z]{0,4}\.) 

Basically, this finds any (alphanumeric) character followed by up to four other alphanumeric characters and a period. This might just work to match the last five characters in front of the period consecutively. It’s hellishly inefficient though, and it only works with engines that allow variable-width lookahead patterns.