Filling a struct based on substring matches within a loop - string

Question

If we take a look at the following code, how can we fill a struct variable with values taken from a slice of strings? https://go.dev/play/p/KkcPzr5r28w
package main
import (
"fmt"
"os"
"strings"
)
type Config struct {
Operation string
Stop string
Start string
File string
}
func ParseConfig(list []string) Config {
var c Config
for _, elem := range list {
if strings.Contains(elem, "op:") {
subList := strings.SplitAfterN(elem, ":", 2)
c.Operation = subList[1]
} else if strings.Contains(elem, "stop:") {
subList := strings.SplitAfterN(elem, ":", 2)
c.Stop = subList[1]
} else if strings.Contains(elem, "start:") {
subList := strings.SplitAfterN(elem, ":", 2)
c.Start = subList[1]
} else if strings.Contains(elem, "file:") {
subList := strings.SplitAfterN(elem, ":", 2)
c.File = subList[1]
}
}
return c
}
func main() {
c := ParseConfig(os.Args[1:])
fmt.Println(c) // {count the quick /tmp/file1.txt}
}
This program doesn't return the right response when invoked with these parameters:
go run scan.go op:count start:quick stop:the file:/tmp/file1.txt
I was wondering what's wrong? What is the best way to refactor the code to solve the problem?

Answer 1

Hopefully I've fixed it, thanks to Gophers's community: https://go.dev/play/p/u_Dc7ctbsib
package main
import (
"fmt"
"strings"
)
type Config struct {
Operation string
Stop string
Start string
File string
}
func main() {
list := []string{"op:count", "start:quick", "stop:the", "file:/tmp/file1.txt"}
fmt.Println(list)
var c Config
for _, v := range list {
if strings.HasPrefix(v, "op:") {
subList := strings.SplitAfterN(v, ":", 2)
c.Operation = subList[1]
} else if strings.Contains(v, "stop:") {
subList := strings.SplitAfterN(v, ":", 2)
c.Stop = subList[1]
} else if strings.Contains(v, "start:") {
subList := strings.SplitAfterN(v, ":", 2)
c.Start = subList[1]
} else if strings.Contains(v, "file:") {
subList := strings.SplitAfterN(v, ":", 2)
c.File = subList[1]
}
}
fmt.Println(c) // {count the quick /tmp/file1.txt}
}
Due to the fact that "stop:the" also wrongly matches "op:", Operation is finally set to "the" instead of "count". The problem seems to be solved now that strings.Contains was replaced with strings.HasPrefix.