英文:
Pass full slice range as parameter
问题
考虑下面的代码，我看到有些代码使用这种格式v[:]来传递完整的切片（而不是其中的一部分）作为参数。
v[:]和v之间有什么区别吗？还是只是开发者的偏好？
我下面进行的测试显示没有区别。我有什么遗漏吗？
package main
import (
"fmt"
)
func main() {
v := []byte {1, 2, 3}
printSliceInfo(v)
printSliceInfo(v[:])
}
func printSliceInfo(s []byte) {
fmt.Printf("Len: %v - Cap: %v - %v\n", len(s), cap(s), s)
}
英文:
Considering the code below, I have seen some code using this format v[:] for pass full slice (not part of it) as parameter.
Is there any difference between v[:] and v? Or it is just a developer preference?
The test I did below show me no difference. Am I missing something?
package main
import (
"fmt"
)
func main() {
v := []byte {1, 2, 3}
printSliceInfo(v)
printSliceInfo(v[:])
}
func printSliceInfo(s []byte) {
fmt.Printf("Len: %v - Cap: %v - %v\n", len(s), cap(s), s)
}
答案1
得分: 3
当 v 是一个切片时，v 和 v[:] 之间没有区别。当 v 是一个数组时，v[:] 是覆盖整个数组的切片。
英文:
When v is a slice, there is no difference between v and v[:]. When v is an array, v[:] is a slice covering the entirety of the array.
答案2
得分: -1
有一个区别。你可能想要阅读Golang规范中的切片表达式
a[:] // 等同于 a[0 : len(a)]
v[:]实际上是一个新的切片值（也就是说你现在有两个切片 - v 和 v[:]），所以在这样做之前你需要考虑为什么真正需要它。在你稍微了解一下切片之后，这里有一些可能帮助你理解区别的东西：https://play.golang.org/p/cJgfYGS78H
附：你上面定义的v := []byte {1, 2, 3}是一个切片，所以数组在这里并不相关。
英文:
There is a difference. You may want to read Slice Expression in the Golang spec
a[:] // same as a[0 : len(a)]
v[:] is actually a new slice value (that is you then have two slices - v & v[:]), so you need to think why you really need it before doing this. Here's something which may help you understand the difference maybe after you read up a bit on slices: https://play.golang.org/p/cJgfYGS78H
p.s.: What you have defined above v := []byte {1, 2, 3} is a slice, so array is not in picture here.
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