package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)(?<=。)(?=\b\d{1,2}[日月])`)
var str = `ZZZ。10月,AAA。11月2日,BBB。CCC。3日,DDD。EEE。12月，FFF
ZZZZZ,10月,AAA。BBB。CCC。`
for i, match := range re.FindAllString(str, -1) {
fmt.Println(match, "found at index", i)
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/