Get the first directory of a path in GO

Question

In Go, is it possible to get the root directory of a path so that

foo/bar/file.txt

returns foo? I know about path/filepath, but

package main

import (
        "fmt"
        "path/filepath"
)

func main() {
        parts := filepath.SplitList("foo/bar/file.txt")
        fmt.Println(parts[0])
        fmt.Println(len(parts))
}

prints foo/bar/file.txt and 1 whereas I would have expected foo and 3.

Oblige

from the docs: > SplitList splits a list of paths joined by the OS-specific ListSeparator, usually found in PATH or GOPATH environment variables. – Brew

ooops. that explains a lot – Oblige

Answer 1

Simply use strings.Split():

s := "foo/bar/file.txt"
parts := strings.Split(s, "/")
fmt.Println(parts[0], len(parts))
fmt.Println(parts)

Output (try it on the Go Playground):

foo 3
[foo bar file.txt]

Note:

If you want to split by the path separator of the current OS, use os.PathSeparator as the separator:

parts := strings.Split(s, string(os.PathSeparator))

filepath.SplitList() splits multiple joined paths into separate paths. It does not split one path into folders and file. For example:

fmt.Println("On Unix:", filepath.SplitList("/a/b/c:/usr/bin"))

Outputs:

On Unix: [/a/b/c /usr/bin]

Udelle

I actually wanted to avoid that due to path separator differences on windows and linux. Is there a solution in the standard library for that? – Oblige

@Stefan: then use os.PathSeparator – Brew

os.PathSeparator is an int so it needs to be converted. – Hurling

Thanks new to go as well i didn't know iw was as simple as that to cast it to a string. – Hurling

Using strings.Split will produce an empty string as the first item when used with an absolute UNIX path. Furthermore it produces two empty strings when used with specific Windows paths. Here is an example: go.dev/play/p/jlBWsVEAzlG – Opus

Answer 2

Note that if you just need the first part, strings.SplitN is at least 10 times faster from my testing:

package main
import "strings"

func main() {
   parts := strings.SplitN("foo/bar/file.txt", "/", 2)
   println(parts[0] == "foo")
}

https://golang.org/pkg/strings#SplitN

Derange