golang map modify key

In Golang, Map is a very commonly used data structure, which allows us to store and access data in the form of key-value pairs. However, sometimes we need to modify a Key in the Map, which is a relatively common operation. However, the Key of Map in Go language is an immutable type, that is, the value of Key is not allowed to be modified. So, how to modify the Key of Map? This article will introduce you to three methods to modify the Key of Golang Map.

Method 1: Delete the old Key first, and then add a new Key

First, we can delete the old Key first, and then add a new Key to the Map. This method is relatively simple and easy to implement, but it requires us to operate the Map twice, which is a bit cumbersome.

The sample code is as follows:

// 创建一个 Map 变量
m := map[string]int{
    "apple":  1,
    "banana": 2,
}

// 删除旧的 Key，并添加一个新的 Key
delete(m, "apple")
m["orange"] = 3

// 输出 Map
fmt.Println(m)

In the above code, we first create a Map variable and assign it two Keys: apple and banana, corresponding to 1 and 2 respectively. Then, we deleted the original Key: apple through the delete() function. Next, we add a new Key to the Map again: orange and assign it a value of 3. Finally, we output this Map through fmt.Println().

Execute the above code and you will get the following output:

map[banana:2 orange:3]

You can see that the original Key: apple has been deleted, leaving only two Keys, banana and orange, in the Map. And Key: orange replaces the original Key: apple.

Of course, this method also has some limitations. If the Key to be deleted does not exist in the Map, this method cannot achieve the purpose of modifying the Key.

Method 2: Use the new Key to overwrite the old Key value

The second method is more straightforward. We can use a new Key to overwrite the old Key value. This method does not require multiple operations on the Map and is relatively simple, but it also has some limitations.

The sample code is as follows:

// 创建一个 Map 变量
m := map[string]int{
    "apple":  1,
    "banana": 2,
}

// 用新的 Key 覆盖旧的 Key 的值
m["apple"] = 3

// 输出 Map
fmt.Println(m)

In the above code, we first create a Map variable and assign it two Keys: apple and banana, corresponding to 1 and 2 respectively. Then, we directly overwrite the old Key value with a new Key: apple, that is, change the value of Key: apple from 1 to 3. Finally, we output this Map through fmt.Println().

Execute the above code and you will get the following output:

map[apple:3 banana:2]

As you can see, we successfully modified the value of Key: apple.

Of course, this method also has its limitations. If the Key to be modified does not exist in the Map, this method cannot achieve the purpose of modifying the Key.

Method 3: Use third-party libraries

In addition to the above two methods, we can also use some third-party libraries to modify the Key of Golang Map. For example, you can use the UUID() function in the gouuid library to generate a new Key and assign it to the original Key. This method is very simple, but it requires us to introduce a third-party library.

The following is a sample code:

import (
    "github.com/satori/go.uuid"
)

// 创建一个 Map 变量
m := map[string]int{
    "apple":  1,
    "banana": 2,
}

// 使用第三方库生成新的 Key，替代旧的 Key
newKey := uuid.NewV4().String()
m[newKey] = m["apple"]
delete(m, "apple")

// 输出 Map
fmt.Println(m)

In the above code, we first introduced the gouuid library to generate a new Key. Then, we created a Map variable and assigned it two Keys: apple and banana, corresponding to 1 and 2 respectively. Next, we use the UUID() function to generate a new Key and assign it to the original Key: apple, that is, replace Key: apple with the new Key. Finally, we delete the old Key: apple through the delete() function. Finally, we output this Map through fmt.Println().

Execute the above code and you will get the following output:

map[4a5e45b7-465b-4b4c-88f1-6d6b3b0ee022:1 banana:2]

As you can see, we used the UUID() function to successfully generate a new Key and add it Replaced the original Key: apple.

Summary

The above are three methods of modifying the Key of Golang Map. Of course, each of these methods has its own advantages and disadvantages, and the appropriate method should be selected according to the actual situation. If you have a better method, please share it in the comment area.

The above is the detailed content of golang map modify key. For more information, please follow other related articles on the PHP Chinese website!