regex to match list of characters and specific words-CodePudding

I'm trying to create a regex username whitelist allowing a specific list of characters and specific list of words (html entities)

This is the current regex that I have ^[a-zA-Z0-9 ,.@\|:()\[\]%_\/'-] $ but I would also want to allow & but I have no idea how to join the two

CodePudding user response：

Use an alternation:

^(?:[a-zA-Z0-9 ,.@\|:()\[\]%_\/'-]|&amp;) $

This simply says to match a character from your current character class or &, one or more times.