Notepad++ How to replace every 11th character (25 characters per line) with a #

Question

I have a set of data - 25 characters long per line by a couple of hundred lines.

Each line / set of 25 characters per line consists of Numbers and Letters (both upper and lowercase)

I want to replace every 11th character (either number or letter) on each line with the character # so instead of

C8P6QagpFPJc4UMtkMAGxz9

I will have

C8P6QagpFP#c4UMtkMAGxz9

Can this be done in Notepad ++

Any assistance welcome.

Thanks,

Robert

Answer 1

With Regular expression selected in the Search Mode, you can do:

Find what:

(^.{10}).(.*)

Replace with:

\1#\2

And press Replace All.

Answer 2

Find what : ^(.{10}).(.*)
Replace with : \1#\2

If you only wish to handle 25-long lines (your data has 23), use : ^(.{10}).(.{14})$