英文:
Easy way to get string pointers
问题
你好！根据你的要求，我将为你翻译以下内容：
我正在使用的一个库有一个非常奇怪的API，经常需要使用字符串指针。目前我是这样做的：
s := "foobar"
weirdFun(&s)
来传递字符串。有没有一种方法可以在不使用变量的情况下完成这个操作？
英文:
A library I am using has a very weird API that often takes string pointers. Currently I am doing this:
s := "foobar"
weirdFun(&s)
to pass strings. Is there a way to do this without the variable?
答案1
得分: 1
Azure SDK使用字符串指针来区分没有值和空字符串。
使用Azure的StringPtr函数来创建指向字符串字面量的指针。
import (
⋮
"github.com/Azure/go-autorest/autorest/to"
)
⋮
res, err := someClient.Create(ctx, someService.ExampleParameters{
Location: to.StringPtr(location),
})
英文:
The Azure SDK uses string pointers to distinguish between no value and the empty string.
Use Azure's StringPtr function to create a pointer to a string literal.
import (
⋮
"github.com/Azure/go-autorest/autorest/to"
)
⋮
res, err := someClient.Create(ctx, someService.ExampleParameters{
Location: to.StringPtr(location),
})
答案2
得分: 1
这个库真的很奇怪，但是你可以使用函数wrap在一行中完成这个操作，例如：
func PointerTo[T ~string](s T) *T {
return &s
}
s := "string"
weirdFun(PointerTo(s))
英文:
The library is really weird, but
you can do this in one line with function wrap, for example
func PointerTo[T ~string](s T) *T {
return &s
}
s := "string"
weirdFun(PointerTo(s))
答案3
得分: 0
也许你应该告知库的作者，在Go语言中，字符串已经是引用类型（指向一个内部表示为rune切片的结构体），因此将字符串传递给函数时不会进行昂贵的复制操作，它是按引用传递的。
希望这能帮到你！
英文:
Maybe you should inform the author of the library, that the strings in Go are already references (to a structure, which is internally represented as a slice of runes), so no expensive copy operation is made by passing string to a function, it's call by reference.
Hope this helps!
答案4
得分: 0
地址操作&x可以与可寻址的值一起使用。
根据语言规范：
操作数必须是可寻址的，也就是说，要么是变量、指针间接引用或切片索引操作；要么是可寻址结构体操作数的字段选择器；要么是可寻址数组的数组索引操作。作为对可寻址要求的例外，x也可以是一个（可能带括号的）复合字面量。
因此，你可以使用复合字面量来解决这个问题：
package main
import (
"fmt"
)
func main() {
s := &"text"
fmt.Printf("value: %v, type: %T\n", &s, &s)
fmt.Printf("value: %v, type: %T\n", &[]string{"literal"}[0], &[]string{"literal"}[0])
}
尽管这是可能的，但我不建议使用这种方法。这不是一个清晰的代码示例。
英文:
The address operation &x can be used with addressable values.
According to the language specification:
> The operand must be addressable, that is, either a variable, pointer indirection, or slice indexing operation; or a field selector of an addressable struct operand; or an array indexing operation of an addressable array. As an exception to the addressability requirement, x may also be a (possibly parenthesized) composite literal.
So, you can work around this using a composite literal:
package main
import (
"fmt"
)
func main() {
s := "text"
fmt.Printf("value: %v, type: %T\n", &s, &s)
fmt.Printf("value: %v, type: %T\n", &[]string{"literal"}[0], &[]string{"literal"}[0])
}
Even though it's possible I don't recommend using this. This is not an example of clear code.
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