String gsub add % before every punctuation character

[Puzzled3d (Puzzled)]

I’ve been trying to write a gsub that converts a string with punctuation, e.g.
Built-In/Roact
Into:
Built%-In%/Roact

I can isolate the punctuation and special characters with [%c%p] but I don’t know how to replace it with itself but with a character infront of it.

[realmile (mile)]

You can put a function as third argument of the gsub which will get called with a string that matched the pattern and needs to return a string:

string.gsub(str,"[%p%c]+",function (m) return "%"..m end)

[Kitsomia (Mia)]

I’m not sure about other nifty tricks regarding gsub but to reference itself is %1.

So in your case,
("Built-In/Roact"):gsub("[%c%p]", "%%%1") | "%%" = "%" and "%1" is the captured result for the provided pattern.

I don’t really know how to word this as I’ve only seen it in a script before and it’s nice for adding radix’s for numbers.

[Puzzled3d (Puzzled)]

Thanks! This works, but @Kitsomia’s answer is more concise so I will use that.