title: Using regular expression for validating data is correct or not?
body: <p>I have been finding some articles and post which suggest not to use the regular expression to validate user data. I am not sure of all the things but i usually find it in case of email address verification. </p>
  
  <p>So i want to be clear whether using regular expression for validating user input is good or not? if it is good then what is bad with it for validating email address?</p>
  
  <p>Edit:</p>
  
  <p>So can we say that for basic primary validation of data types we can use regex and it is good and for full validation we need to combine it with another parser.</p>
  
  <p>And for second part for email validation in general usage we can use it but as per standard it is not appropriate. Is it? </p>
  
  <p>Now confusion in selecting correct one answer</p>