Go语言中高效地处理集合的方法小结

package main

import "fmt"

func main() {
    // 创建一个切片
    numbers := []int{1, 2, 3, 4, 5}

    // 添加元素
    numbers = append(numbers, 6)

    // 遍历切片
    for i, num := range numbers {
        fmt.Printf("Index: %d, Value: %d\n", i, num)
    }
}

package main

import "fmt"

func main() {
    // 创建一个 map
    ages := map[string]int{
        "Alice": 30,
        "Bob":   25,
        "Carol": 28,
    }

    // 查找元素
    if age, ok := ages["Bob"]; ok {
        fmt.Printf("Bob's age is %d\n", age)
    } else {
        fmt.Println("Bob not found")
    }

    // 添加元素
    ages["Dave"] = 32

    // 删除元素
    delete(ages, "Carol")

    // 遍历 map
    for name, age := range ages {
        fmt.Printf("%s is %d years old\n", name, age)
    }
}

package main

import (
    "fmt"
    "sync"
)

func main() {
    var m sync.Map

    // 存储元素
    m.Store("key1", "value1")
    m.Store("key2", "value2")

    // 加载元素
    if value, ok := m.Load("key1"); ok {
        fmt.Println("key1:", value)
    }

    // 删除元素
    m.Delete("key2")

    // 遍历 map
    m.Range(func(key, value interface{}) bool {
        fmt.Println(key, value)
        return true
    })
}

package main

import (
    "fmt"
    "sort"
)

func main() {
    // 创建一个切片
    numbers := []int{5, 2, 9, 1, 5, 6}

    // 对切片进行排序
    sort.Ints(numbers)

    // 输出排序后的切片
    fmt.Println(numbers)
}

package main

import (
    "container/heap"
    "fmt"
)

// 定义一个最小堆
type IntHeap []int

func (h IntHeap) Len() int           { return len(h) }
func (h IntHeap) Less(i, j int) bool { return h[i] < h[j] }
func (h IntHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *IntHeap) Push(x interface{}) {
    *h = append(*h, x.(int))
}

func (h *IntHeap) Pop() interface{} {
    old := *h
    n := len(old)
    x := old[n-1]
    *h = old[0 : n-1]
    return x
}

func main() {
    h := &IntHeap{2, 1, 5}
    heap.Init(h)

    heap.Push(h, 3)
    fmt.Printf("minimum: %d\n", (*h)[0])

    for h.Len() > 0 {
        fmt.Printf("%d ", heap.Pop(h))
    }
}

package main

import "fmt"

func main() {
    // 创建一个切片
    src := []int{1, 2, 3, 4, 5}

    // 创建一个目标切片
    dst := make([]int, len(src))

    // 复制切片
    copy(dst, src)

    // 输出目标切片
    fmt.Println(dst)
}

package main

import "fmt"

func main() {
    // 预分配切片的容量
    numbers := make([]int, 0, 10) // 长度为0，容量为10
    numbers = append(numbers, 1, 2, 3)

    // 预分配映射的容量
    ages := make(map[string]int, 100) // 容量为100
    ages["Alice"] = 30

    fmt.Println(numbers, ages)
}

package main

import (
    "fmt"
    "sync"
)

func process(num int, wg *sync.WaitGroup) {
    defer wg.Done()
    fmt.Println("Processing:", num)
}

func main() {
    var wg sync.WaitGroup
    numbers := []int{1, 2, 3, 4, 5}

    for _, num := range numbers {
        wg.Add(1)
        go process(num, &wg)
    }

    wg.Wait()
    fmt.Println("All goroutines finished")
}