golang中range问题

Question

示例代码packagemainimport("fmt""time")typenewFieldstringfunc(fnewField)print(){fmt.Println(f)}funcmain(){data:=[]newField{"one","two","thred"}for_,v:=rangedata{gov.print()//printonetwothreegofunc(){fmt.Println(v)}()//printthreethreethree}time.Sleep(3*time.Second)}疑问range过程中，两种打印方式，为什么打印的结果不同呢?

Answer 1

闭包的问题，v.print()是依次调用的是"one","two","three"的print方法。第二个goroutine引用了循环变量v，goroutine未启动时，v就改变了，所以不一致，但是不一定是three,three,three，与运行时的调度有关
                            

Answer 2

经典的golangfor-range陷阱。Google下就知道了
funcmain(){
data:=[]newField{"one","two","thred"}
for_,v:=rangedata{
tmp:=v
gofunc(){fmt.Println(tmp)}()
gofunc(){fmt.Println("addr:",&v,",value:",v)}()//printthreethreethree
}
time.Sleep(3*time.Second)
}
可以运行下这个程序。gov.print()等同于赋值后，再执行Println。“v”的地址一直没变，所以打印出来的都是最后一次的赋值，即"three"