Basic usage and modification methods of Golang Map

Golang is a programming language known for its performance and concurrency advantages. One of its built-in data structures is Map. Map is an unordered collection of key-value pairs, similar to a dictionary or hash table in other languages. In Golang, Map is created using the make() function. Its basic usage and modification methods are as follows.

Basic usage

First, let’s take a look at how to declare and initialize a Map:

package main

import "fmt"

func main() {
    // 创建一个空的Map
    var m map[string]int
    m = make(map[string]int)
    
    // 添加键值对
    m["apple"] = 10
    m["banana"] = 20

    // 访问键值对
    fmt.Println("apple:", m["apple"])
    fmt.Println("banana:", m["banana"])

    // 删除键值对
    delete(m, "apple")

    // 判断键是否存在
    value, ok := m["apple"]
    if ok {
        fmt.Println("apple存在，值为：", value)
    } else {
        fmt.Println("apple不存在")
    }

    // 遍历Map
    for key, value := range m {
        fmt.Println(key, ":", value)
    }
}

Modification methods

In addition to basic addition, access, and deletion In addition to key-value pairs, we can also modify the values ​​in the Map through direct assignment:

package main

import "fmt"

func main() {
    m := make(map[string]int)

    m["apple"] = 10
    fmt.Println("apple的值为：", m["apple"])

    // 直接赋值修改
    m["apple"] = 15
    fmt.Println("修改后的apple的值为：", m["apple"])
}

In addition, we can also determine whether the key exists and then modify the key-value pair to ensure that it does not An error occurred because of accessing a non-existent key:

package main

import "fmt"

func main() {
    m := make(map[string]int)

    m["apple"] = 10

    if value, ok := m["apple"]; ok {
        m["apple"] = value + 5
        fmt.Println("修改后的apple的值为：", m["apple"])
    } else {
        fmt.Println("apple不存在")
    }
}

In general, Map in Golang is a very convenient and practical data structure, suitable for storing key-value pairs, and its basic usage and modification methods are also All very simple and intuitive. Through the introduction of this article, I believe that readers have a deeper understanding of the basic usage and modification methods of Map in Golang.

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