In this post, I will add my notes related to regex use in day to day development.
email Validation Regex, Picked up from Angular Js Code
^(?=.{1,254}$)(?=.{1,64}@)[-!#$%&’*+\/0-9=?A-Z^_`a-z{|}~]+(\.[-!#$%&’*+\/0-9=?A-Z^_`a-z{|}~]+)*@[A-Za-z0-9]([A-Za-z0-9-]{0,61}[A-Za-z0-9])?(\.[A-Za-z0-9]([A-Za-z0-9-]{0,61}[A-Za-z0-9])?)*$
in-built angularJs email validation, which has following length limit :
64-Chars@63-Chars.63-Chars (local-part@domain-part) (as per the RFC : IETF )
If only to have numbers and dots in a string, usually on version matches
^[0-9,.]*$
Sumit Arora 