如何使用golang检查数组中的重复元素？

问题描述：

I have made a code to generate random numbers and delete the repeated ones like below:

package main

import (
    "fmt"
    "math/rand"
    "time"
)

func main() {
    list := [7]int{}
    for i := 0; i < 7; i++ {
    here:
        rand.Seed(time.Now().UnixNano())
        s := rand.Intn(16)
        fmt.Println(s)
        if s != list[0] && s != list[1] && s != list[2] && s != list[3] && s != list[4] && s != list[5] && s != list[6] {
            list[i] = s
        } else {
            goto here
        }

    }
    fmt.Println("list:", list)
}

I noticed that there were a lot repeated code like:

s!=list[0]&&list[1]

But when I write it to:

s!=list[0:6]

It is wrong, how can I do this properly?

答

Store it in map.

like that

rndmap := make(map[int]bool)

for len(rndmap) < YOUR_LEN {
    rndmap[rand.Intn(YOUR_MAX_RAND)] = true
}

Result map will never store repeated indexes.

You can convert it into slice like this

rndslice := make([]int,0)
for i, _ := range rndmap {
    rndslice = append(rndslice, i)
}

答

If you want a way to check a slice of ints for a value, try this function (play.golang.org):

func InSlice (arr []int, val int) (bool){
    for _, v := range(arr) {
         if v == val { return true; } 
    }    
    return false; 
}

You can use this like below, but you won't be able to run it succesfully on play.golang.org because play.golang.org has a deterministic response to math/rand (In my case, it's 0), which will keep it from giving more than one answer, forcing this code into an infinite loop.

func main() {
    list := [7]int{}
    for i := 0; i < 7; i++ {
    here:
        rand.Seed(time.Now().UnixNano())
        s := rand.Intn(16)
        fmt.Println(s)
        if !InSlice(list[:], s) {
            list[i] = s
        } else {
            goto here
    }

}

答

You can use the standard library to generate the random elements without any repetition in the first place.

package main

import (
    "fmt"
    "math/rand"
)

func main() {
    fmt.Println(rand.Perm(16)[:7])
}

如何使用golang检查数组中的重复元素？

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