在Go語(yǔ)言中，new()用于分配并返回指向任意類型的零值指針，而make()則專門用于初始化切片、映射和通道。具體區(qū)別如下：1.new(T)分配內(nèi)存并返回*T類型指針，適用于需要指向結(jié)構(gòu)體或基礎(chǔ)類型的指針且無(wú)需復(fù)雜初始化的場(chǎng)景；2.make()僅用于slice、map和chan類型，它不僅分配內(nèi)存還進(jìn)行內(nèi)部結(jié)構(gòu)設(shè)置，使這些類型可直接使用；3.new()返回的是指針，make()返回的是實(shí)際類型的非指針實(shí)例；4.new()適用于任何類型，make()僅限特定內(nèi)置類型。兩者用途不同，不可互換。

In Go, make() and new() are both built-in functions used for allocation, but they serve different purposes and are used in different contexts. Understanding when to use each is key to writing effective Go code.

When to Use new()

new(T) is used to allocate memory for a type T and returns a pointer to the zero value of that type. It doesn’t initialize the value beyond setting it to its default (like 0 for integers, false for booleans, nil for pointers).

For example:

p := new(int)
fmt.Println(*p) // prints: 0

This creates a pointer to an integer with the initial value of 0. You’ll typically use new() when you need a pointer to a struct or a basic type, especially if you want to avoid manually initializing it to zero yourself.

A common case might be:

type User struct {
    Name string
    Age  int
}

u := new(User)
// u is now a pointer to a User with empty Name and Age 0

Just remember, new() gives you a pointer, and it only zeroes out the memory — it doesn’t do any custom initialization logic.

When to Use make()

make() is specifically for initializing slices, maps, and channels. These types require more than just allocating memory — they need internal structure setup to be usable.

You can't use make() for arbitrary types; it only works with those three built-in types.

Examples:

s := make([]int, 0, 5) // slice with length 0, capacity 5
m := make(map[string]int) // empty map ready to use
c := make(chan int) // unbuffered channel

Using make() ensures these types are properly initialized so you can start appending to slices, putting values into maps, or sending data through channels right away.

If you tried to declare them without make() like this:

var m map[string]int
m["key"] = 42 // panic: assignment to entry in nil map

You'd get a runtime error because the map wasn't initialized.

Key Differences Summary

• Purpose:

  • new() allocates memory and zeroes it.
  • make() initializes certain types (slice, map, chan) so they're ready for use.

• Return Type:

  • new(T) returns *T.
  • make() returns the actual type (T, not *T).

• Usability:

  • new() works with any type.
  • make() only works with slices, maps, and channels.

So while both help with memory management, they’re not interchangeable — make() handles more complex setup for specific types, and new() simply allocates and zeros.

That’s basically it. They each have their own role, and once you know what kind of type you're dealing with, choosing between them becomes straightforward.

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