本文关注Golang中for循环开启goroutine的执行顺序问题。实验表明，for循环本身比在循环中启动goroutine快；然而，启动goroutine与第一个fmt.Println的执行速度可能接近。特别是，第二个for循环的fmt比goroutine中的fmt更快，可能是由于channel操作的延迟。最后，main函数结束时，goroutine中的某些任务可能仍未完成。
突然想到了之前一直没留意的for循环中开goroutine的执行顺序问题，就找了段代码试了试，试了几次后发现几个有意思的地方，我暂时没有精力往更深处挖掘，希望有golang大神能简单说一说这几个地方是怎么回事。
代码：
package main import "fmt" func Count(ch chan int) { fmt.Println("Count doing") ch <- 1 fmt.Println("Counting") } func main() { chs := make([]chan int, 100) for i := 0; i < 100; i++ { chs[i] = make(chan int) go Count(chs[i]) fmt.Println("Count",i) } for i, ch := range chs { <-ch fmt.Println("Counting ", i) } }试了几次之后，反复的想goroutine执行的问题。
根据下面的输出，我能看到的是：
1. for循环的速度 比 for中开出goroutine并执行的速度 执行的快
2. 但是 开goroutine和执行第一个fmt的速度可能赶上 for循环的速度 比如前12个count和count doing
3. 关键问题，第二个for循环执行的fmt竟然要比goroutine中的第二个fmt快？？（放入channel很耗时？）
4. main结束时，也就是第二个for循环结束时， 还有goroutine中的第二个fmt没执行输出：
Count 0 Count 1 Count 2 Count 3 Count 4 Count 5 Count 6 Count 7 Count 8 Count 9 Count 10 Count 11 Count doing Count doing Count doing Count doing Count doing Count 12 Count doing Count doing Count doing Count doing Count doing Count doing Count doing Count 13 Count 14 Count 15 Count 16 Count 17 Count 18 Count 19 Count 20 Count 21 Count doing Count doing Count doing Count 22 Count doing Count doing Count doing Count 23 Count 24 Count 25 Count 26 Count 27 Count 28 Count 29 Count 30 Count doing Count 31 Count doing Count doing Count 32 Count 33 Count 34 Count 35 Count doing Count 36 Count doing Count doing Count 37 Count 38 Count doing Count doing Count doing Count doing Count 39 Count 40 Count 41 Count 42 Count 43 Count doing Count doing Count 44 Count 45 Count 46 Count 47 Count doing Count 48 Count 49 Count doing Count doing Count 50 Count 51 Count doing Count doing Count doing Count doing Count doing Count 52 Count 53 Count doing Count doing Count doing Count doing Count 54 Count doing Count 55 Count 56 Count 57 Count 58 Count 59 Count 60 Count 61 Count 62 Count 63 Count 64 Count 65 Count doing Count doing Count doing Count 66 Count 67 Count 68 Count 69 Count doing Count 70 Count doing Count 71 Count 72 Count doing Count 73 Count doing Count doing Count 74 Count doing Count 75 Count 76 Count 77 Count doing Count doing Count doing Count doing Count 78 Count 79 Count 80 Count 81 Count 82 Count 83 Count 84 Count 85 Count 86 Count 87 Count 88 Count 89 Count 90 Count 91 Count 92 Count 93 Count 94 Count doing Count doing Count doing Count doing Count doing Count doing Count doing Count doing Count 95 Count doing Count 96 Count doing Count 97 Count 98 Count doing Count 99 Count doing Count doing Counting 0 Counting 1 Counting 2 Counting 3 Counting 4 Counting 5 Counting 6 Count doing Count doing Counting 7 Counting 8 Count doing Counting Count doing Counting 9 Counting Count doing Count doing Count doing Count doing Count doing Counting Count doing Count doing Count doing Counting Count doing Counting Count doing Counting 10 Counting 11 Counting Count doing Count doing Count doing Count doing Count doing Count doing Counting Count doing Count doing Counting Counting Count doing Count doing Count doing Count doing Counting Count doing Counting Count doing Count doing Counting 12 Counting 13 Counting 14 Counting 15 Counting 16 Counting 17 Counting 18 Counting 19 Counting 20 Counting 21 Counting 22 Counting 23 Counting 24 Counting 25 Counting 26 Counting 27 Counting 28 Counting 29 Counting 30 Counting 31 Counting 32 Counting 33 Counting 34 Counting 35 Counting 36 Counting 37 Counting 38 Counting 39 Counting 40 Counting 41 Counting 42 Counting 43 Counting 44 Counting 45 Counting 46 Counting 47 Counting 48 Counting 49 Counting 50 Counting 51 Counting 52 Counting 53 Counting 54 Counting 55 Counting 56 Counting Counting Counting Counting Counting Counting Count doing Counting Count doing Counting Counting Counting 57 Counting 58 Counting 59 Counting 60 Counting 61 Counting 62 Counting 63 Counting 64 Counting 65 Counting 66 Counting 67 Counting 68 Counting 69 Counting 70 Counting 71 Counting 72 Counting 73 Counting 74 Counting 75 Counting 76 Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting Counting 77 Counting 78 Counting 79 Counting 80 Counting 81 Counting 82 Counting 83 Counting 84 Counting 85 Counting 86 Counting 87 Counting 88 Counting 89 Counting 90 Counting 91 Counting 92 Counting 93 Counting 94 Counting 95 Counting 96 Counting 97 Counting 98 Counting 99
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