How to check if a string contain 2 same char in a row?-CodePudding

I have a regex like this

REGEX_2_SAME_CHARACTER_IN_A_ROW = "^(?:(.)(?!\\1\\1))*$"

and check password with that regex if it contain 2 same character in a row

contain2SameCharacterInARow, err := regexp.MatchString(REGEX_2_SAME_CHARACTER_IN_A_ROW, password)

but I get this error

error match regex 2 same char in a row: error parsing regexp: invalid or unsupported Perl syntax: `(?!`

I have read other question that using regexp.MustCompile but I don't know how to handle or code it, is there anyone can help me with the solution?

Here you can check my full code for validate password https://play.golang.com/p/5Fj4-UPvL8s

CodePudding user response：

You don't need the anchor, the non-capturing group, nor the negative lookahead. Simply match and capture any character ((.)) followed by itself (\\1).

REGEX_2_SAME_CHARACTER_IN_A_ROW = "(.)\\1"

But this brings us to the next problem: Go regexes do not support back references, so you need to find a different solution. One would be looping the string yourself.