英文:
Golang: override initial elements of a slice
问题
我想初始化一个长度为3的空整数切片，将随机整数存储在切片中，并在每次迭代时对切片进行排序。以下代码实现了这一目标：
package main
import (
"fmt"
"math/rand"
"sort"
)
func main() {
myslice := make([]int, 3)
for i := 0; i < 10; i++ {
myslice = append(myslice, rand.Intn(100))
sort.IntSlice(myslice).Sort()
fmt.Println(myslice)
}
}
最终结果：[0 0 0 5 23 28 43 45 50 57 68 76 87] 但是，在追加新元素之前，我还想覆盖初始元素（也就是去掉那些零）。由于切片在每次迭代时都是排序的，如果 i < 3，调用 myslice[i] = rand.Intn(100) 并不一定有效。
我的初始解决方案是编写一个函数来获取 i < 3 的第一个零值的索引，并用新的随机值替换该索引... 但是，我想知道是否有更好的方法来覆盖切片的初始值。
英文:
I want to initialize an empty integer slice of length 3, store random ints in the slice, and sort the slice at each iteration. This code accomplishes that:
package main
import (
"fmt"
"math/rand"
"sort"
)
func main() {
myslice := make([]int, 3)
for i := 0; i < 10; i++ {
myslice = append(myslice, rand.Intn(100))
sort.IntSlice(myslice).Sort()
fmt.Println(myslice)
}
}
End result: [0 0 0 5 23 28 43 45 50 57 68 76 87] However, I would also like to override the initial elements (in other words, get rid of those zeroes) before appending new elements. Since the slice is sorted at each iteration, calling myslice[i] = rand.Intn(100) if i < 3 wouldn't necessarily work.
My initial solution is to write a function to get the first index of zero for i < 3, and replace that index with a new random value... however, I was wondering whether there is a better option to override the initial values of a slice.
答案1
得分: 5
使用以下代码创建一个新的[]int切片，长度为0，容量为3：
myslice := make([]int, 0, 3)
尽管你要添加的元素超过了3个，但这样做实际上没有太多意义；如果你要预先分配内存，就预先分配整个切片；如果你不打算预先分配整个切片，只需使用var myslice []int即可。
这个问题在《Go 语言之旅》中有详细介绍，我强烈建议你去完成一下。这只需要几分钟时间，涵盖了所有的语言基础知识。
英文:
Use:
myslice := make([]int, 0, 3)
to create a new []int with length 0 and capacity 3. Though since you're appending more than 3 elements, this is fairly pointless; if you're going to preallocate, preallocate the whole thing, and if you're not going to preallocate the whole thing, just use var myslice []int.
This is covered in the Tour of Go, which I highly recommend going through. It only takes a few minutes and covers all the language basics.
答案2
得分: 2
根据Adrian的建议，将代码修改如下：
package main
import (
"fmt"
"math/rand"
"sort"
)
func main() {
var myslice []int
for i := 0; i < 10; i++ {
myslice = append(myslice, rand.Intn(100))
sort.IntSlice(myslice).Sort()
fmt.Println(myslice)
}
}
输出结果：
[81]
[81 87]
[47 81 87]
[47 59 81 87]
[47 59 81 81 87]
[18 47 59 81 81 87]
[18 25 47 59 81 81 87]
[18 25 40 47 59 81 81 87]
[18 25 40 47 56 59 81 81 87]
[0 18 25 40 47 56 59 81 81 87]
英文:
Based on the suggestion of Adrian ,modifying the code as follows:
package main
import (
"fmt"
"math/rand"
"sort"
)
func main() {
var myslice []int
for i := 0; i < 10; i++ {
myslice = append(myslice, rand.Intn(100))
sort.IntSlice(myslice).Sort()
fmt.Println(myslice)
}
}
Output:
[81]
[81 87]
[47 81 87]
[47 59 81 87]
[47 59 81 81 87]
[18 47 59 81 81 87]
[18 25 47 59 81 81 87]
[18 25 40 47 59 81 81 87]
[18 25 40 47 56 59 81 81 87]
[0 18 25 40 47 56 59 81 81 87]
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