Regular expression to exclude specific words but allow certain patterns

Question

I am generating a regular expression that can contain any letters or numbers or an underscore [a-zA-Z0-9_] but not contain words that exactly match log , login and lastly test .

Can anybody help me with this?

Answer 1

You can use this negative lookahead regex:

\b(?!log(?:in)?|test)\w+

RegEx Demo

(?!log(?:in)?|test) is negative lookahead, that will fail the match if any given words log,login,test are present.

Answer 2

 ^(?!(^test$)|(^log$)|(^login$))([A-Za-z0-9_-/]+)$ 

Did the trick for me. Thanks for your answers guys

Answer 3

我认为下面的正则表达式应该可以解决问题

^((?!log|login|test)[a-zA-Z0-9_])*$