Analytics supports regular expressions and assist the creation of more flexible definitions for things like view filters, goals, segments, audiences, content groups, and channel groupings.
In the context of Analytics, regular expressions are a specific sequences of characters that broadly or narrowly match patterns in your Analytics data. Google Analytics RegEx ease the decision making process by making it more accurate, faster and efficient.
To read more: https://seoanalyst.me/how-to-use-regex- ... on-making/