golang获取一串数字中与给定数最接近的数字

今天需要写一个算法，获取一串数字中与给定数最接近的数字，代码如下

package main

import (

    "fmt"
)

func main(){
    arr:=[]int{12,16,29,34,39,43,55,64,71,89,90,9}
    zuijin:=get_zuijin(40,arr)
    fmt.Println(zuijin)
}

func get_zuijin(this int,arr []int) int{
    min:=0
    if this==arr[0]{
        return arr[0]
    }else if this>arr[0]{
        min = this-arr[0]
    }else if this<arr[0]{
        min = arr[0]-this
    }

    for _,v:=range arr{
        if v==this{
            return v
        }else if v>this{
            if min>v-this{
                min = v-this
            }
        }else if v<this{
            if min>this-v{
                min = this-v
            }
        }
    }

    for _,v:=range arr{
        if this+min == v{
            return v
        }else if this-min == v{
            return v
        }
    }
    return min
}