What is under the hood of the map in Go? How is it implemented?

In Go, a map is implemented as a hash table with open addressing and chaining to resolve collisions. Under the hood, the structure contains an array of buckets, each of which stores multiple key-value pairs. When adding a key, a hash is computed to determine the bucket. If there are collisions in the bucket, they are resolved using a linked list or alternative methods.

Implementation features:

• Uses a hashing algorithm optimized for speed and uniform distribution.
• When the number of elements grows, rehashing occurs with an increase in the number of buckets.
• The order of iteration over map elements is not guaranteed in Go.

Example of using a map:

m := make(map[string]int)
m["apple"] = 5
m["banana"] = 3

for k, v := range m {
    fmt.Println(k, v)
}

Thus, a map in Go is an efficient data structure for fast key-based access, implemented through a hash table with optimizations for performance and security.