Test your regular expressions
When you create view filters or custom report filters, you can use regular expressions for increased flexibility. An easy way to test your regular expressions on your own data is to navigate directly to the reports in your view and use the advanced table-filter feature.
For example, if you want a filter to include pages whose titles or URLs match a particular pattern, navigate to the Content > Site Content > All Pages report, click the advanced table filter, and change the match type to Matching RegExp. This allows you to quickly see which pages are included using your regular expression. You can also use the same concept to test hostname view filters by navigating to the Audience > Technology > Network report and changing the primary dimension to hostname.