泛型详解

1. 类型参数

func Map[T any, U any](s []T, f func(T) U) []U {
    result := make([]U, len(s))
    for i, v := range s {
        result[i] = f(v)
    }
    return result
}

doubled := Map([]int{1, 2, 3}, func(x int) int { return x * 2 })

2. 约束

type Number interface {
    int | int8 | int16 | int32 | int64 |
    float32 | float64
}

func Sum[T Number](nums []T) T {
    var total T
    for _, n := range nums {
        total += n
    }
    return total
}

3. comparable

func Contains[T comparable](slice []T, target T) bool {
    for _, v := range slice {
        if v == target {
            return true
        }
    }
    return false
}

4. 泛型类型

type Stack[T any] struct {
    items []T
}

func (s *Stack[T]) Push(item T) {
    s.items = append(s.items, item)
}

func (s *Stack[T]) Pop() (T, bool) {
    if len(s.items) == 0 {
        var zero T
        return zero, false
    }
    top := s.items[len(s.items)-1]
    s.items = s.items[:len(s.items)-1]
    return top, true
}