types - go中某个值的动态类型是什么意思？

Question

考虑到 go是静态类型的语言，一些值的动态类型是什么意思？

Answer 1

在处理接口(interface)值时，变量的“动态类型”很重要。动态类型定义如下(source):

The static type (or just type) of a variable is the type defined by its declaration. Variables of interface type also have a distinct dynamic type, which is the actual type of the value stored in the variable at run time. The dynamic type may vary during execution but is always assignable to the static type of the interface variable. For non-interface types, the dynamic type is always the static type.

考虑这个例子:

var someValue interface{} = 2

someValue 的静态类型是 interface{} 但动态类型是 int 并且可能非常好在未来改变。示例:

var someValue interface{} = 2

someValue = "foo"

在上面的示例中，someValue 的动态类型从 int 更改为 string。