Regular expression for 6 characters

Question

I need couple of regular expression in ASP.NET.

1. First should accept only 6 characters and second and third character should accept only _ (underscore).

   Like: a__cde

2. And I want one other regex that should also take 6 characters and at second position it should accept only underscore (_) and at third position it should accept maybe underscore (_) or hash (#) and at fourth position it should accept only hash (#).

Note: In both the regex user can only enter: Number, Alphabets or Star (*) at any position instead of above mentioned positions.

Can any one help me out on this? I have tried by below website:

http://www.regexr.com/

But not able to generate proper regex.

Answer 1

Try something like:

1. ^[a-zA-Z0-9\*]__[a-zA-Z0-9\*]{3}$
2. ^[a-zA-Z0-9\*]_[_#]#[a-zA-Z0-9\*]{2}$