Regular expression (regex) is supported in the Metric Explorer and can be added to filter detail metrics in a chart. The examples in this topic show you how to create regex strings for filtering detail metric keys, such as status codes and IP addresses.
In the ExtraHop system, regex is most effective when you want to filter detail metric data by a parameter contained within the detail metric key, such as a number within any IP address. Regex is also effective for excluding specific keys from charts or displaying a specific combination of keys. Learn more about drilling down for detail metrics as you edit a chart.
|Chart Scenario||Regex filter||How it works|
|Compare HTTP status codes 200 to 404.||(200|404)||Matches 200 and 404 codes where the | symbol serves as an OR function.|
|Display any HTTP status code that contains a 4.||||Matches any value that contains a 4. For example, this filter can return 204 and 400 status codes.|
|Display all 500-level HTTP status codes.||^||Matches any value that begins with a 5. For example, this filter can return 500 and 502 status codes.|
|Display all 400 and 500-level HTTP status codes.||^||Matches all values that begin with a 4 or 5. For example, this filter can return 400, 403, and 500 status codes.|
|Display any HTTP status codes except 200-level status codes.||^(?!2)||Matches all values except values beginning with a 2, where ^(?!) specifies the range of results to exclude. For example, this filter can return 400, 500, and 302 status codes.|
|Display any IP address with a 187.||187.||Matches 1, 8, and 7 characters in the IP address.|
|Review all IP addresses containing 187.18.||187\.18\.||Matches 187 and the character . that follows the 187. For example, this filter returns results for 220.127.116.11.0, 18.104.22.168.0, or 22.214.171.124.0/16.|
|Display any IP address except 126.96.36.199.||[^188.8.131.52]||Matches anything except 184.108.40.206, where [^] specifies the exact value to exclude.|
|Exclude a list of specific IP addresses||[^220.127.116.11|18.104.22.168|22.214.171.124]||Matches anything except 126.96.36.199, 188.8.131.52, and 184.108.40.206, where the | symbol serves as an OR function and [^] specifies the exact values to exclude.|