如何找到两段字符串之间的差异

Question

这是我想要的结果

slice1 := []string{"foo", "bar","hello"}
slice2 := []string{"foo", "bar"}

difference(slice1, slice2)
=> ["hello"]

我正在寻找两个字符串切片之间的区别！

原文由 samol 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

根据切片的大小，不同的解决方案可能是最好的。

我的回答假设顺序无关紧要。

使用简单循环，仅用于较小的切片：

 package main

import "fmt"

func difference(slice1 []string, slice2 []string) []string {
    var diff []string

    // Loop two times, first to find slice1 strings not in slice2,
    // second loop to find slice2 strings not in slice1
    for i := 0; i < 2; i++ {
        for _, s1 := range slice1 {
            found := false
            for _, s2 := range slice2 {
                if s1 == s2 {
                    found = true
                    break
                }
            }
            // String not found. We add it to return slice
            if !found {
                diff = append(diff, s1)
            }
        }
        // Swap the slices, only if it was the first loop
        if i == 0 {
            slice1, slice2 = slice2, slice1
        }
    }

    return diff
}

func main() {
    slice1 := []string{"foo", "bar", "hello"}
    slice2 := []string{"foo", "world", "bar", "foo"}

    fmt.Printf("%+v\n", difference(slice1, slice2))
}

输出：

 [hello world]

游乐场： http ://play.golang.org/p/KHTmJcR4rg

原文由 ANisus 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

假设 Go 映射是 ~O(1)，这是一个 ~O(n) 差分函数，它适用于未排序的切片。

 // difference returns the elements in `a` that aren't in `b`.
func difference(a, b []string) []string {
    mb := make(map[string]struct{}, len(b))
    for _, x := range b {
        mb[x] = struct{}{}
    }
    var diff []string
    for _, x := range a {
        if _, found := mb[x]; !found {
            diff = append(diff, x)
        }
    }
    return diff
}

原文由 peterwilliams97 发布，翻译遵循 CC BY-SA 4.0 许可协议