How to split a string and assign it to variables

Question

Two steps, for example,

package main

import (
    "fmt"
    "strings"
)

func main() {
    s := strings.Split("127.0.0.1:5432", ":")
    ip, port := s[0], s[1]
    fmt.Println(ip, port)
}

Output:

127.0.0.1 5432

One step, for example,

package main

import (
    "fmt"
    "net"
)

func main() {
    host, port, err := net.SplitHostPort("127.0.0.1:5432")
    fmt.Println(host, port, err)
}

Output:

127.0.0.1 5432 <nil>

Since go is flexible an you can create your own python style split ...

package main

import (
    "fmt"
    "strings"
    "errors"
)

type PyString string

func main() {
    var py PyString
    py = "127.0.0.1:5432"
    ip, port , err := py.Split(":")       // Python Style
    fmt.Println(ip, port, err)
}

func (py PyString) Split(str string) ( string, string , error ) {
    s := strings.Split(string(py), str)
    if len(s) < 2 {
        return "" , "", errors.New("Minimum match not found")
    }
    return s[0] , s[1] , nil
}

The IPv6 addresses for fields like RemoteAddr from http.Request are formatted as "[::1]:53343"

So net.SplitHostPort works great:

package main

    import (
        "fmt"
        "net"
    )

    func main() {
        host1, port, err := net.SplitHostPort("127.0.0.1:5432")
        fmt.Println(host1, port, err)

        host2, port, err := net.SplitHostPort("[::1]:2345")
        fmt.Println(host2, port, err)

        host3, port, err := net.SplitHostPort("localhost:1234")
        fmt.Println(host3, port, err)
    }

Output is:

127.0.0.1 5432 <nil>
::1 2345 <nil>
localhost 1234 <nil>

package main

import (
    "fmt"
    "strings"
)

func main() {
    strs := strings.Split("127.0.0.1:5432", ":")
    ip := strs[0]
    port := strs[1]
    fmt.Println(ip, port)
}

Here is the definition for strings.Split

// Split slices s into all substrings separated by sep and returns a slice of
// the substrings between those separators.
//
// If s does not contain sep and sep is not empty, Split returns a
// slice of length 1 whose only element is s.
//
// If sep is empty, Split splits after each UTF-8 sequence. If both s
// and sep are empty, Split returns an empty slice.
//
// It is equivalent to SplitN with a count of -1.
func Split(s, sep string) []string { return genSplit(s, sep, 0, -1) }

Golang does not support implicit unpacking of an slice (unlike python) and that is the reason this would not work. Like the examples given above, we would need to workaround it.

One side note:

The implicit unpacking happens for variadic functions in go:

func varParamFunc(params ...int) {

}

varParamFunc(slice1...)