While I'm no expert with regular expressions (regex), a little knowledge goes a long way. Here are the resources I find useful.
Regex stands for 'regular expression'. But what are regular expressions? Simply put, they are patterns used to match (find) sequences of characters in a string. You could use regular expressions to match whole words, parts of words, or more complex patterns such as numbers beginning with a '£' symbol.
It is worthwhile having some familiarity with regex because it crops up in so many different contexts. Google Analytics, for example, supports the use of regular expressions in filters, goals and segments.
While I'm no expert with regular expressions (regex), a little knowledge goes a long way. Here are the resources I find useful.