druzuz321103 2012-11-22 21:18 采纳率: 100%
浏览 6721
已采纳

如何检查Go中的字符串切片是否包含某个值?

检查某个值是否在字符串片中的最佳方法是什么?我会用其他语言的集合,但是Go没有。到目前为止,我最大的努力是:.

package main

import "fmt"

func main() {
    list := []string{"a", "b", "x"}
    fmt.Println(isValueInList("b", list))
    fmt.Println(isValueInList("z", list))
}

func isValueInList(value string, list []string) bool {
    for _, v := range list {
        if v == value {
            return true
        }
    }
    return false
}

http://play.golang.org/p/gkwMz5j09n

这个解决方案对于小片应该是可以的,但是对于有许多元素的片应该怎么做呢?

  • 写回答

3条回答 默认 最新

  • douxun4924 2012-11-22 21:26
    关注

    If you have a slice of strings in an arbitrary order, finding if a value exists in the slice requires O(n) time. This applies to all languages.

    If you intend to do a search over and over again, you can use other data structures to make lookups faster. However, building these structures require at least O(n) time. So you will only get benefits if you do lookups using the data structure more than once.

    For example, you could load your strings into a map. Then lookups would take O(1) time. Insertions also take O(1) time making the initial build take O(n) time:

    set := make(map[string]bool)
    for _, v := range list {
        set[v] = true
    }
    
    fmt.Println(set["b"])
    

    You can also sort your string slice and then do a binary search. Binary searches occur in O(log(n)) time. Building can take O(n*log(n)) time.

    sort.Strings(list)
    i := sort.SearchStrings(list, "b")
    fmt.Println(i < len(list) && list[i] == "b")
    

    Although in theory given an infinite number of values, a map is faster, in practice it is very likely searching a sorted list will be faster. You need to benchmark it yourself.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
查看更多回答(2条)

报告相同问题?

悬赏问题

  • ¥20 Python安装cvxpy库出问题
  • ¥15 用前端向数据库插入数据,通过debug发现数据能走到后端,但是放行之后就会提示错误
  • ¥15 python天天向上类似问题,但没有清零
  • ¥30 3天&7天&&15天&销量如何统计同一行
  • ¥30 帮我写一段可以读取LD2450数据并计算距离的Arduino代码
  • ¥15 C#调用python代码(python带有库)
  • ¥15 矩阵加法的规则是两个矩阵中对应位置的数的绝对值进行加和
  • ¥15 活动选择题。最多可以参加几个项目?
  • ¥15 飞机曲面部件如机翼,壁板等具体的孔位模型
  • ¥15 vs2019中数据导出问题