How can I match any duplicate character with regexp?

Question

I need to combine any character that repeats twice, for example:

"abccdeff"

Must match "cc" and "ff". In any other regex syntax, let me use Javascript as a quick example, I could do:

var str = "abccdeff";
var r = /([a-z]{1})\1/g
console.log(str.match(r))

What returns

[ 'cc', 'ff' ]

But Regexp Go does not seem to allow this. Is it possible to do this in Go?

Answer 1

Since backreference is not supported by re2 , you will need:

• either use another regex library (for example glenn-brown/golang-pkg-pcre)
• or encode a loop that performs analysis without regular expression