Vim is looking for a pattern, and if NOT meets the delete string

Question

I read this question, but I want to know how I can delete a row when the pattern does not appear.

Answer 1

Removing the rest of the line when the pattern does not occur is ... so that I can understand.

Did you mean delete the entire line if it does not have a template?

:v/pattern/d 

If you had in mind, keep the string, but collect the characters:

 :v/pattern/s/.*// 

Answer 2

Equivalent:

 :g!/pattern/d 

It’s easier to remember, in my opinion, because ! rooted as "not" in my brain.

Answer 3

 :v/pattern/s/.*//