将nil字符串指针设置为空字符串 [英] Set nil string pointer to empty string

问题描述

如何将类型中的字符串指针的引用值设置为空字符串? 考虑以下示例:

How do I set the referenced value of a string pointer in a type to the empty string? Consider this example:

package main

import (
    "fmt"
)

type Test struct {
    value *string
}

func main() {
    t := Test{nil}
    if t.value == nil {
        // I want to set the pointer's value to the empty string here
    }

    fmt.Println(t.value)
}

我尝试了&和*运算符的所有组合都无济于事:

I've tried all combinations of the & and * operators to no avail:

t.value = &""
t.value = *""
&t.value = ""
*t.value = ""

其中一些显然很傻，但是我没有发现尝试的危害. 我也尝试使用reflect和SetString:

Obviously some of those are silly, but I didn't see the harm in trying. I also tried using reflect and SetString:

reflect.ValueOf(t.value).SetString("")

这会导致编译错误

恐慌:反映:使用无法寻址的值reflect.Value.SetString

panic: reflect: reflect.Value.SetString using unaddressable value

我假设这是因为Go中的字符串是不可变的?

I'm assuming that's because strings in Go are immutable?

推荐答案

字符串文字不是可寻址.

获取包含空字符串的变量的地址:

Take the address of variable containing the empty string:

s := ""
t.value = &s

或使用新的:

t.value = new(string)

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