I've looked at some of the other IP matching that seems a lot more complex but several of them don't work, and I'm too simple minded to figure out why. Keep it simple, I've never had a problem matching IP addresses in logs with this one.

Matches email with groups for username and domain.

checks for ie 11 user agent

Parses date-time duration strings +-1y2M3d4h5m6s, where 'm' is the dafault. Like this, where {} contains list of capturing groups: 21 - parsed as {,,,,21,} 2y2s - parsed as {2,,,,,2}

use this to get value of any side of an equation. You can combine this with https://regex101.com/r/fH5kJ1/1

Is a simple regex for compare tel number of El Salvador (not use +503 or iquals)

Chinese salary input

Un pequeño regex para validar si el telefono pertenece a El Salvador

search text matching any word