The Go Playground Imports embed package main import ( "fmt" "regexp" ) var dbrex = regexp.MustCompile(`derpibooru.org/(\d+)`) func main() { fmt.Printf("%#v", dbrex.FindStringSubmatch("[IMAGE: New #943330] https://derpibooru.org/943330 (564x1417 JPEG)")) } About the Playground The Go Playground is a web service that runs on golang.org 's servers. The service receives a Go program, compiles, links, and runs the program inside a sandbox, then returns the output. There are limitations to the programs that can be run in the playground: The playground can use most of the standard library, with some exceptions. The only communication a playground program has to the outside world is by writing to standard output and standard error. In the playground the time begins at 2009-11-10 23:00:00 UTC (determining the significance of this date is an exercise for the re...