go两种遍历chan
go中对通道chan遍历有两种方式一种是用range另一种为for select。
package main import ( "fmt" "strings" ) func main() { intChan0 := make(chan int, 10) for i := 0; i < 10; i++ { intChan0 <- i } close(intChan0) for i := range intChan0 { fmt.Printf("range i value is %d, pointer is %d\n", i, &i) } fmt.Println(strings.Repeat("-", 20)) intChan1 := make(chan int, 10) for i := 0; i < 10; i++ { intChan1 <- i } close(intChan1) forLoop: for { select { case i, ok := <-intChan1: if !ok { break forLoop } fmt.Printf("for select i value is %d, pointer is %d\n", i, &i) } } }
上面打印结果为
range i value is 0, pointer is 824633794752 range i value is 1, pointer is 824633794752 range i value is 2, pointer is 824633794752 range i value is 3, pointer is 824633794752 range i value is 4, pointer is 824633794752 range i value is 5, pointer is 824633794752 range i value is 6, pointer is 824633794752 range i value is 7, pointer is 824633794752 range i value is 8, pointer is 824633794752 range i value is 9, pointer is 824633794752 -------------------- for select i value is 0, pointer is 824633794760 for select i value is 1, pointer is 824633794768 for select i value is 2, pointer is 824633794776 for select i value is 3, pointer is 824633794784 for select i value is 4, pointer is 824633794792 for select i value is 5, pointer is 824633794800 for select i value is 6, pointer is 824633794808 for select i value is 7, pointer is 824633794816 for select i value is 8, pointer is 824633794824 for select i value is 9, pointer is 824633794832
使用golang版本为1.21,可以看出,rang读取chan内元素,其指针一样,for select每次不同。
通常情况下,当有其他for select有其他case分支使用for select。