"Golang" Golang closure and Goroutine in the process of changing variables

This is a created article in which the information may have evolved or changed.

Conclusion:
Closures can access variables in the outer code;
Foe cycle and gotoutine execution simultaneously;
All variables that operate on the goroutine are variables that manipulate the outer code directly, and the value of the variables in the outer code depends on the node that the loop executes.

Correct code:

package mainimport ("fmt""sync")func main() {var s []string = []string{    "first",    "second",    "third",}var waitGroup sync.WaitGroupwaitGroup.Add(len(s))for _, item := range s {    go func(i string) {        fmt.Println(item)        waitGroup.Done()    }(item)}waitGroup.Wait()}

Output:

firstsecondthird

Error instance:

for _, item := range s {    go func() {        fmt.Println(item)        waitGroup.Done()    }()}

Output:

thirdthirdthird

The following examples can explain what happens above:

for _, item := range s {    go func() {        fmt.Println(item)        waitGroup.Done()    }()            time.Sleep(1 * time.Second)}

Output:

thirdthirdthird