How to get map in golang

In Go language, you can easily use map to store and access key-value pairs. Map is a collection type that can be used to store some unordered data and can quickly access the values ​​​​through keys. In this article, we will introduce various methods on how to get map in golang.

1. Using subscripts

Under normal circumstances, we can use subscripts to obtain the values ​​in the map. The example is as follows:

m := make(map[string]string)
m[“a”] = “apple”
m[“b”] = “banana”
fmt.Println(m[“a”]) // apple
fmt.Println(m[“b”]) // banana

We You only need to use the [key] format to access the value in the map, where key must be the key name stored in the map. If key does not exist, then a zero value of the type corresponding to the value will be returned.

2. Using ok-idiom

Sometimes, we need to more accurately determine whether a specific key exists in the map. At this time, we can use ok-idiom. The example is as follows:

m := make(map[string]string)
m[“a”] = “apple”
m[“b”] = “banana”
value, ok := m[“c”]
if ok {
    fmt.Println(value) // 不会被触发
} else {
    fmt.Println(“key c does not exist”)
}

Here we can see that ok-idiom is like an extended form of if condition, which can be used to determine whether a specific key exists in our map. If the key exists in the map, then the return value of ok will be true and the corresponding value will be obtained. Otherwise, we need to use the else branch statement to print the error message.

3. Using for-range

In some cases, we need to traverse the entire map and then access all key-value pairs in it. In this case, we can use for- range loop, the example is as follows:

m := make(map[string]string)
m[“a”] = “apple”
m[“b”] = “banana”
for key, value := range m {
    fmt.Printf(“%s -> %s
”, key, value)
}

The for-range loop here is very similar to the foreach loop in other languages, and is used to iteratively access each key-value pair in the map. We need to use special syntax to specify the key and value variable names separately in the loop. During the iteration process, we can obtain the data in each key-value pair in turn and process it in a key-value manner.

To sum up, the above are several commonly used methods to obtain map in golang. For each scenario, we can choose the corresponding method to obtain and access map data. When writing code, please choose the appropriate method according to the actual situation and handle errors.

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