# go遇到的一些问题
### chan关闭之后，还可以读写吗？
> 不能写，但可以读
~~~
package main
import (
"fmt"
"sync"
)
func main() {
var ret = make(chan []int, 1000)
var wg = sync.WaitGroup{}
wg.Add(3)
go func() {
defer wg.Done()
var result = make([]int, 0)
for i := 0; i < 10; i++ {
result = append(result, i)
}
ret <- result
}()
go func() {
defer wg.Done()
var result = make([]int, 0)
for i := 10; i < 20; i++ {
result = append(result, i)
}
ret <- result
}()
go func() {
defer wg.Done()
var result = make([]int, 0)
for i := 20; i < 30; i++ {
result = append(result, i)
}
ret <- result
}()
wg.Wait()
//go func() {
// for {
// ret <- []int{1}
// time.Sleep(time.Second)
// }
//}()
//close(ret)
for v := range ret { //0 range if v==0 break ,or panic
for _, v := range v {
fmt.Println(v)
}
}
}
~~~
### 并发获取数据，常见问题
~~~
for _,v:=range uids{
go func(){
fmt.Println(v)//v的值是一样的！
}()
}
==》
for _,v:=range uids{
go func(v int){
fmt.Println(v)//v的值正常
}(v)
}
~~~
