Why Can't I Take the Address of a Map Value in Go?

Why Map Values Remain Unreachable in Go

In Go, map values are not addressable. This means that you cannot take the address of a map value, as demonstrated in the example code:

var mymap map[int]string = make(map[int]string)
mymap[1] = "One"
var myptr *string = &mymap[1]
fmt.Println(*myptr)

This code generates an error indicating that map values are not addressable. This behavior contrasts with其他语言, such as C , where map values can be addressed.

The Go developers made this design decision to ensure the validity of map entries. Maps in Go are implemented using hash tables. Hash tables undergo internal reorganizations to optimize performance and maintain load balance. If map values were addressable, these addressable values could become invalid during such reorganizations.

This is why Go restricts the addressability of map values to prevent errors and ensure data integrity within the map. While this may seem like a drawback, it ultimately contributes to the stability and reliability of map operations in Go.

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