I want to match string that contain "server-key" but not if the string start with "test-"

For example input:

1. dummy "test-server-key-asd" dummy
2. dummy "server-key-qwe" dummy
3. server-key-wer
4. a server-key-ert
5. test-server-key

The output will be

server-key-qwe
server-key-wer
server-key-ert

With a negative lookbehind, the regex will be (?<!test-)server-key-[a-z]{3}

What is the alternative negative lookbehind for this regex in Go? because Go doesn't support negative lookbehind.

CodePudding user response：

Workaround

Effectively, you cannot use negative lookbehind. But you could capture what's before and after to see if it's only server-key, surounded by spaces, simple or double quotes:

(^|[\s"'])(server-key)([\s"']|$)

I added ^ at the beginning and $ and the end, in case your match isn't surounded by spaces or quotes.

You could then just use capture group 2 and forget group 1 and 3.

Playing around here: https://regex101.com/r/grRpZC/1

This way you cannot match something like server-keys or mysql-server-key which I imagine you don't want to match.

Workaround improved

But the solution isn't very bullet proof since we probably could have server-key surounded by some other chars, such as [](){}%*.... And we don't want to list them all. But we could say that server-key should not be surounded by any non-latin char, hyphen or number. This can be done with the help of \p{L} (or \p{Letter}) which matches any letter from any language. It's probably better than using [a-z] in case of accents or whatever.

We don't want to match letters, hyphens or numbers, so this would be: [^\p{L}\d-]

Putting it back into the regex we get:

(^|[^\p{L}\d-])(server-key)([^\p{L}\d-]|$)

Full test here: https://regex101.com/r/1oPZXb/1

CodePudding user response：

There is no way in Golang using only regex.

But this regex will capture the target including any prefix

[a-z-]*server-key-[a-z]{3}

Then test that what's captured doesn't start with "test-":

if !strings.HasPrefix(s, "test-")