Trim multiple characters to right of final slash including slash

Golang doesn't have the strrchr function that php does. If I want to remove /path (including the final slash) from this string, how does one do it in golang?

 mystr := "/this/is/my/path" 

Desired output

"/this/is/my"

I can get the index of the final slash like this

lastSlash := strings.LastIndex(mystr, "/")

but I'm not sure how to create a new string with /path removed. How to do that?

Try output := mystr[:strings.LastIndex(mystr, "/")]

mystr := "/this/is/my/path" 
idx := strings.LastIndex(mystr, "/")
if idx != -1{
  mystr = mystr[:idx]
}

fmt.Println(mystr)

playground link

captncraig's answer works for any type of separator char, but assuming you are running on a POSIX-style machine ("/" is the path separator) and what you are manipulating are indeed paths:

http://play.golang.org/p/oQbXTEhH30

package main

import (
	"fmt"
	"path/filepath"
)

func main() {
	s := "/this/is/my/path"
	fmt.Println(filepath.Dir(s))

    // Output: /this/is/my
}

From the godoc (https://golang.org/pkg/path/filepath/#Dir):

> Dir returns all but the last element of path, typically the path's directory. After dropping the final element, the path is Cleaned and trailing slashes are removed.

Though if you run it with /path, it will return /, which may or may not be what you want.

One corner case not covered by the previous (quite satisfactory) solutions is that of a trailing /. Ie - if you wanted /foo/bar/quux/ trimmed to /foo/bar rather than /foo/bar/quux. That can be accomplished with the regexp library:

mystr := "/this/is/my/path/"
trimpattern := regexp.MustCompile("^(.*?)/[^/]*/?$")
newstr := trimpattern.ReplaceAllString(mystr, "$1")

fmt.Println(newstr)

There's a bit fuller example here: http://play.golang.org/p/ii-svpbaHt