Golang - mapping an variable length array to a struct

I have a struct as follows:

type MyStruct struct {
   Part1 string
   Part2 string
   Part3 string
}

I have a string separated by slashes that I want to map to this:

part1/part2/part3

However, the string may only contain 1 part such as part1 or two parts such as part1/part2

if any part is missing it much be mapped as an empty string.

I am very new to go so wondering what the best way to achieve this is. Typically i would split the string and check the length to know what to do. In go is there a more elegant way to do this?

Here's a version of peterSO's solution that uses a wrapper to help simplify the logic.

package main

import (
	"fmt"
	"strings"
)

type Wrap []string

func (w Wrap) Get(i int) string {
	if 0 <= i && i < len(w) {
		return w[i]
	}
	return ""
}

type MyStruct struct {
	Part1 string
	Part2 string
	Part3 string
}

func main() {
	str := "part1/part2/part3"
	split := Wrap(strings.Split(str, "/"))
	var parts MyStruct
	parts.Part1 = split.Get(0)
	parts.Part2 = split.Get(1)
	parts.Part3 = split.Get(2)
	fmt.Println(parts)

	str = "part1/part2"
	split = Wrap(strings.Split(str, "/"))
	parts = MyStruct{}
	parts.Part1 = split.Get(0)
	parts.Part2 = split.Get(1)
	parts.Part3 = split.Get(2)
	fmt.Println(parts)
}

package main

import (
	"fmt"
	"strings"
)

type MyStruct struct {
	Part1 string
	Part2 string
	Part3 string
}

func (m *MyStruct) set(s string) *MyStruct {
	p := []*string{&m.Part1, &m.Part2, &m.Part3}
	for i, v := range strings.Split(s+"//", "/")[:3] {
		*p[i] = v
	}
	return m
}

func main() {
	var v MyStruct
	fmt.Printf("%#v\n", v.set("foo"))
	fmt.Printf("%#v\n", v.set(""))
	fmt.Printf("%#v\n", v.set("bar/baz"))
	fmt.Printf("%#v\n", v.set("alpha//omega"))
	fmt.Printf("%#v\n", v.set("/var/mail"))
}

Playground

Output:

&main.MyStruct{Part1:"foo", Part2:"", Part3:""}
&main.MyStruct{Part1:"", Part2:"", Part3:""}
&main.MyStruct{Part1:"bar", Part2:"baz", Part3:""}
&main.MyStruct{Part1:"alpha", Part2:"", Part3:"omega"}
&main.MyStruct{Part1:"", Part2:"var", Part3:"mail"}

For example,

package main

import (
	"fmt"
	"strings"
)

type MyStruct struct {
	Part1 string
	Part2 string
	Part3 string
}

func main() {
	str := "part1/part2/part3"
	split := strings.Split(str, "/")
	var parts MyStruct
	if len(split) > 0 {
		parts.Part1 = split[0]
		if len(split) > 1 {
			parts.Part2 = split[1]
			if len(split) > 2 {
				parts.Part3 = split[2]
			}
		}
	}
	fmt.Println(parts)
}

Output:

{part1 part2 part3}

Expanding on dyoo's answer with shorter syntax and renamed types as I bypassed it for these two reasons, however it is the most extensible and reliable solution. The real benefit comes if you need to change from 3 to n elements, all that is required is a change to your struct definition and initialisation. StrSlice type is also very reusable when ever default values are required for a slice of strings.

package main

import (
    "fmt"
    "strings"
)

type MyStruct struct {
    Part1 string
    Part2 string
    Part3 string
}

type StrSlice []string

func (s StrSlice) Get(i int) string {
    if i >= 0 && i < len(s) {
        return s[i]
    }
    return ""
}

func main() {

    str := "part1/part2/part3"
    slice := StrSlice(strings.Split(str, "/"))
    parts := MyStruct{slice.Get(0),slice.Get(1),slice.Get(2)}
    fmt.Println(parts)

}