前言
主要是涉及到深浅拷贝相关的,但是在看的一个资料过程中发现他有错...并且一系列,复制粘贴他的,也都错了。
错误文章指路
很显然,Copy是深拷贝啊!!!
Copy功能
copy的代码很少,如下:
go
// The copy built-in function copies elements from a source slice into a
// destination slice. (As a special case, it also will copy bytes from a
// string to a slice of bytes.) The source and destination may overlap. Copy
// returns the number of elements copied, which will be the minimum of
// len(src) and len(dst).
func copy(dst, src []Type) int
一共就一个dst,一个src,一共俩切片。
功能上,简单来说就是:实现切片的拷贝。需要注意的是,这里的拷贝是深拷贝,但1、目标切片需要提前初始化。2、只能直接拷一层。
官方文档在https://golangbyexample.com/copy-function-in-golang/
其中介绍如下:
If the length of src is greater than the length of dst, then the number of elements copied is the length of dst
If the length of dst is greater than length of src, then number of elements copied is length of src
Basically the number of elements copied is minimum of length of (src, dst).
即对应的这篇文章所说的情况1------https://www.jianshu.com/p/be07bee40b08
官方文档中的下一句:
Also to note that once the copy is done then any change in dst will not reflect in src and vice versa unless both src and dst refer to the same slice.
对应的即使此文中的情况2------https://www.jianshu.com/p/be07bee40b08
官方文档之后举例了,可以用copy自己拷贝到自己的情况,这个在网络教程中没怎么搜到。
go
package main
import "fmt"
func main() {
src := []int{1, 2, 3, 4, 5}
numberOfElementsCopied := copy(src, src[3:])
fmt.Printf("Number Of Elements Copied: %d\n", numberOfElementsCopied)
fmt.Printf("src: %v\n", src)
}
总结
这个没什么多的内容,但就是说,官方文档比来回cv的那些教程高大上一万倍。。。