英文:
golang pointer in range doesn't work
问题
为什么结果是 A:&{[{[{1}]}]}A:&{[{[{2}]}]}A:&{[{[{2}]}]} 而不是 A:&{[{[{1}]}]}A:&{[{[{2}]}]}A:&{[{[{3}]}]}？我们不能在 range 循环中使用指针吗？这是代码，我在 range 循环中设置了一个指针，但它失败了。
package mainimport ("fmt")type A struct {Barry []B}func (this *A) init() {b := &B{}b.init()this.Barry = []B{*b}return}type B struct {Carry []C}func (this *B) init() {c := &C{}c.init()this.Carry = []C{*c}return}type C struct {state string}func (this *C) init() {this.state = "1"return}func main() {a := &A{}a.init()fmt.Printf("A:%v\n", a)p := &a.Barry[0].Carry[0]p.state = "2"fmt.Printf("A:%v\n", a)for _, v := range a.Barry[0].Carry {if v.state == "2" {p = &v}}p.state = "3"fmt.Printf("A:%v\n", a)}
英文:
Why the result is A:&{[{[{1}]}]}A:&{[{[{2}]}]}A:&{[{[{2}]}]}
not: A:&{[{[{1}]}]}A:&{[{[{2}]}]}A:&{[{[{3}]}]}
we can't use pointer in range?
here is the code, I set a pointer, pointed in the range loop, but it fails.
package mainimport("fmt")type A struct{Barry []B}func (this *A)init(){b:=&B{}b.init()this.Barry=[]B{*b}return}type B struct{Carry []C}func (this *B)init(){c:=&C{}c.init()this.Carry=[]C{*c}return}type C struct{state string}func (this *C)init(){this.state="1"return}func main(){a:=&A{}a.init()fmt.Printf("A:%v\n",a)p:=&a.Barry[0].Carry[0]p.state="2"fmt.Printf("A:%v\n",a)for _,v:=range a.Barry[0].Carry{if v.state=="2"{p=&v}}p.state="3"fmt.Printf("A:%v\n",a)}
答案1
得分: 0
变量p被设置为指向v，而不是切片元素。这段代码将p设置为指向切片元素：
for i, v := range a.Barry[0].Carry {if v.state == "2" {p = &a.Barry[0].Carry[i]}}
英文:
The variable p is set to point at v, not to the slice element. This code sets p to point at the slice element:
for i, v := range a.Barry[0].Carry {if v.state == "2" {p = &a.Barry[0].Carry[i]}}
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