golang中的new和make到底有什么区别？

// The new built-in function allocates memory. The first argument is a type,
// not a value, and the value returned is a pointer to a newly
// allocated zero value of that type.
func new(Type) *Type

new 开辟一块内存，用来存储Type类型的变量，返回指向该地址的指针。
Type可以为所有类型。
给变量赋值零值 zero value of that type。

一下是各个类型的零值：

bool
-> false
numbers
-> 0
string
-> ""
struct
-> 各自key的零值
pointers -> nil
slices -> nil
maps -> nil
channels -> nil
functions -> nil
interfaces -> nil

有些类型的零值是nil，这个又是什么鬼，可以参考阅读 https://blog.csdn.net/raoxiaoya/article/details/108705176
值为nil的变量是没法操作的。

p := new([]int)
fmt.Println(*p == nil)
// true 
fmt.Printf("%pn", p)
// 0xc0000044a0
fmt.Println(*p)
// []
(*p)[0] = 1
// panic: runtime error: index out of range [0] with length 0

从这个意义上来讲
p := new([]int) 与 var p *[]int 的区别在于后者是nil pointer。

new 常用在需要生成零值的结构体指针变量

p := new(Per)

等价于

p := &Per{}

接下来看一看make

// The make built-in function allocates and initializes an object of type
// slice, map, or chan (only). Like new, the first argument is a type, not a
// value. Unlike new, make's return type is the same as the type of its
// argument, not a pointer to it. The specification of the result depends on
// the type:
//	Slice: The size specifies the length. The capacity of the slice is
//	equal to its length. A second integer argument may be provided to
//	specify a different capacity; it must be no smaller than the
//	length. For example, make([]int, 0, 10) allocates an underlying array
//	of size 10 and returns a slice of length 0 and capacity 10 that is
//	backed by this underlying array.
//
//	Map: An empty map is allocated with enough space to hold the
//	specified number of elements. The size may be omitted, in which case
//	a small starting size is allocated.
//
//	Channel: The channel's buffer is initialized with the specified
//	buffer capacity. If zero, or the size is omitted, the channel is
//	unbuffered.
func make(t Type, size ...IntegerType) Type

make 开辟一块内存，用来存储Type类型的变量，返回此变量。
Type只能是 slice, map, chan。
初始化类型的值 initializes an object of type。因为它们三个的零值是nil，没法使用，因此还需要进一步赋予合理的值，叫做初始化。

a := make([]int, 1, 10)
b := make(map[string]string)
c := make(chan int, 1)

最后

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