package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)(^|[^a-z])\((\d*|[a-z])\)`)
var str = `(x+2)/(x) -> only select ( ) in (x)
-(2)+. -> only select ( ) in (2)
(wsd). -> select nothing
(x)^2+2 -> only select ( ) in (x)
sin(x). -> select nothing
(22313)a. -> only select ( ) in (22313)
+23-3()/(3x)+(x). -> only select () in () and ( ) in (x)
sin(x)+3*x^2+(x)+23 -> only select ( ) in (x)`
var substitution = "$1$2"
fmt.Println(re.ReplaceAllString(str, substitution))
}
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/