func (s *Sample) Append(name string) {
d := &Stuff{
name: name,}
s.data = append(s.data,d)
}
但不是当你这样做：
func (s Sample) Append(name string) {
d := &Stuff{
name: name,d)
}
有什么理由为什么要使用第二个例子。
我应该定义值或指针的方法吗？
func (s *MyStruct) pointerMethod() { } // method on pointer
func (s MyStruct) valueMethod() { } // method on value
First,and most important,does the method need to modify the receiver? If it does,the receiver must be a pointer. (Slices and maps act as references,so their story is a little more subtle,but for instance to change the length of a slice in a method the receiver must still be a pointer.)
In the examples above,if pointerMethod modifies the fields of s,the caller will see those changes,but valueMethod is called with a copy of the caller’s argument (that’s the definition of passing a value),so changes it makes will be invisible to the caller.
在你的情况下，func(s Sample)Append(name string)修改一个副本。
laher提醒我们in the comments使用一个值而不是指针也意味着获取一个副本，并尊重对象的不变性::
You’d want to use the non-pointer
valueMethodwhen (for nstance) you’re returning a [value derived from an] ‘immutable’ private property.
参见“Why are receivers pass by value in Go?”：
Can be useful if for instance you have a small immutable object. The caller can know for certain that this method doesn’t modify it’s receiver. They can’t know this if the receiver is a pointer without reading the code first.
