regex - Regular expression to mask strings using string substitution

Question

I would like to use a regular expression to mask all but the first three alphanumeric characters of each word in a string using a mask character (such as "x"), so "1 Buckingham Palace Road, London" would become "1 Bucxxxxxxx Palxxx Roax, Lonxxx".

Keeping the first three characters is easily done using

s/(w{0,3})(.*)/$1/g

but I cannot seem to figure out how to insert length($2) times the masking character instead of $2.

Thanks!

Answer 1

C#:

new Regex(@"(?<!.{0,2}).").Replace("1 Buckingham Palace Road, London", "x");

Since you say it's language-agnostic, I trust this can be easily ported into your language of choice...

Or, you could just get the length of $2 and fill the x's the old fashioned way.