Maps

Maps are Go's built-in associative data type (sometimes called hashes or dicts in other languages). Maps are unordered collections of key-value pairs. Maps are declared using the map keyword, followed by the key and value types in square brackets. The key type must be comparable (i.e. it must support the == operator). The value type can be any type.

// [...]

func main() {
    m := make(map[string]int) // create empty map
    m["key1"] = 10            // set value
    m["key2"] = 20            // set value
    fmt.Println(m)            // map[key1:10 key2:20]

    m["key1"] = 30 // update value
    fmt.Println(m) // map[key1:30 key2:20]

    delete(m, "key1") // delete key
    fmt.Println(m)   // map[key2:20]

    v, ok := m["key1"] // check if key exists
    fmt.Println(v, ok) // 0 false

    val2 := m["key2"] // get value
    fmt.Println(val2) // 20
}

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