grabs the ID for the regex101.com permalink to code

The BNF rules from RFC 5322 transformed to PCRE by Nikita Popov and described in the post http://nikic.github.io/2012/06/15/The-true-power-of-regular-expressions.html.

Matches distorted email addresses and converts them back to real ones.

A quite neat regular expression for URLs, e-mails..., I found on Matthew O'Riordan's blog.

Captures all fields from a CSV file's line. Can be customized with user-defined field separator and protecting character.

Matches any valid JSON object, matches recursively. Passes all JSON test cases I found.

1-15 alphanumeric login name

Checks for valid UK/British postcodes. There was another on here that had for some reason been upvoted, but it was actually incorrect as it worked on none of my valid own postcodes! Namely that it assumed two letters and a number (BS3) when you can have variations (M20). Allows for an optional spac...

From a (fairly large) list of User Agent strings, extract the OS, Browser, and Device Type.

Validate and capture dateTime parts, includes validation for leap years, range 1000-2999. Fixed bug

Capture comma separated numbers, no matter if there are spaces before or after the commas.

Validate cron lines (even the ones commented out)