package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?i)(?<!\w)(?:http://www\.example\.com)?/(\S+?)\.pdf\b`)
var str = `some containing string http://www.example.com/subfolder/name.pdf or /subfolder/name.pdf
<a href="/pdf/subdir/name.pdf">clickhere</a><a href="/pdf/subdir/name.pdf">2nd PDF</a>`
var substitution = "/wp-content/uploads/old/$1.pdf"
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/