FWIW I'm doing the Accessing Web Data part of the Python for Informatics course at Coursera. First part of that course is regex and after one lesson (~15 mins) it covers enough to read the above expression.
I was already cognisant with regex, so I'm perhaps biased, but a simple email-like search seems easy for a novice to read.
Perhaps you have a particular block when approaching regex. The book by Charles Severance that goes with the course (above) is freely available online.
Nope, I'm mostly a DB guy very fluent in SQl and I use regex like two dozen time a year.But every time I nead to write something not trivial I must run to a regex cheatsheat website and spend long minutes trying to figure shit out.
It's not that I'm dumb and taking a MOOC about regex is definitely on my todo list... It's just that I haven't found the damn time yet to learn monstrosity and exceptions of regex.
And this is especially painful coming from PostgreSQL which have a good debugger and a clear syntax (even for non standard functions).