RFC 2822 (and 822) allow the domain to be a simple domain with NO ".", but this pattern requires a compound domain at least one "." in the domain name, as per RFC 2821 (4.1.2). In this article you will learn how to match numbers and number range in Regular expressions. RFC 2822 (and 822) do allow embedded comments, whitespace, and newlines within *some* parts of an email address, but this pattern above DOES NOT. Based on its Base value, a number has unique representation an.
See this thread for more info, including a version that does not use. Decimal Number System - Number System represents value of number with respect to its given base.
This pattern uses (.NET/Perl only?) features named group "(?As of version 3.6 all kinds of numbers can have '' in them, but it can't be first or. Floating point numbers can be in exponent form. Integers include decimal, binary, octal, and hexadecimal forms. If you really a regex that will match ALL valid forms of Python numbers, it will be a complex regex. (Note, no attempt is made to fully validate an IPv6 address-literal.) But seriously, Python numbers are complicated. This accepts RFC 2822 email addresses in the form:ĭomain = rfc2821domain | rfc2821domain-literalĪn rfc 2821 domain (EXCEPT that the final sub-domain must consist of 2 or more letters only).