有什么有效的方法来获取Go中两个切片的交集吗?
我想避免嵌套for循环之类的解决方案
slice1 := []string{"foo", "bar","hello"} slice2 := []string{"foo", "bar"} intersection(slice1, slice2) => ["foo", "bar"]
字符串顺序无关紧要
是的,有几种不同的解决方法。.这是一个可以优化的示例。
package main import "fmt" func intersection(a []string, b []string) (inter []string) { // interacting on the smallest list first can potentailly be faster...but not by much, worse case is the same low, high := a, b if len(a) > len(b) { low = b high = a } done := false for i, l := range low { for j, h := range high { // get future index values f1 := i + 1 f2 := j + 1 if l == h { inter = append(inter, h) if f1 < len(low) && f2 < len(high) { // if the future values aren't the same then that's the end of the intersection if low[f1] != high[f2] { done = true } } // we don't want to interate on the entire list everytime, so remove the parts we already looped on will make it faster each pass high = high[:j+copy(high[j:], high[j+1:])] break } } // nothing in the future so we are done if done { break } } return } func main() { slice1 := []string{"foo", "bar", "hello", "bar"} slice2 := []string{"foo", "bar"} fmt.Printf("%+v\n", intersection(slice1, slice2)) }
现在上面定义的交集方法将只运行在slices的strings,比如你的例子。您可以在理论上创建一个定义,这个样子的func intersection(a []interface, b []interface) (inter []interface),但是你会依靠反射和类型转换,这样就可以比较,这将增加延迟和使您的代码更难阅读。对于您关心的每种类型,维护和阅读以编写单独的函数可能更容易。
slices
strings
func intersection(a []interface, b []interface) (inter []interface)
func intersectionString(a []string, b []string) (inter []string),
func intersectionString(a []string, b []string) (inter []string)
func intersectionInt(a []int, b []int) (inter []int),
func intersectionInt(a []int, b []int) (inter []int)
func intersectionFloat64(a []Float64, b []Float64) (inter []Float64),..ect
func intersectionFloat64(a []Float64, b []Float64) (inter []Float64)
然后,您可以创建自己的包并在确定要实现的方式后重用。
package intersection func String(a []string, b []string) (inter []string) func Int(a []int, b []int) (inter []int) func Float64(a []Float64, b []Float64) (inter []Float64)