for quadratic equations ||ax^2+bx+c=d||

Regex to match USD currency in a text

Even though using a delimiter within a string, without escaping it, is an illegal character, sometimes this still happens and we need to extract a HTML value.

This regex is to describe the password which has at least 7 characters (OC) with at least a special one (SC). Of course, we know the SC may be in the first, second .... or last of the password. Also, we know the password maybe bigger than just 8. so I wrote the RE to accept any character (AC) from !...

'www.xakep.ru' === xakep 'http://github.com/carbonfive/raygun' === github 'https://www.cnet.com' === cnet 'xewveqmwcz90sl64.co/' === xewveqmwcz90sl64

Extracts and returns the domain name from a given URL.

Matches everything before after // or www and before a period. If needed, replace the matched elements with blanks.