How does map work inside?

In Go, a map is implemented as a hash table with open addressing and dynamic resizing.

Key points of map operation:

• Hashing the key: When adding or searching for an element, the key is hashed using the built-in hash function.

• Buckets: The hash value is used to determine the bucket where the key-value pair is stored. Each bucket contains multiple slots.

• Collisions: If multiple keys hash to the same bucket, they are stored as an array or linked list within the bucket.

• Dynamic resizing: When a certain load factor is reached, the map expands — more buckets are created, and elements are redistributed.

• Security: In Go, the hash function for maps is randomized at program startup to prevent hash table attacks.

Example of using a map:

m := make(map[string]int)
m["apple"] = 5
value, ok := m["apple"]
if ok {
    fmt.Println("Value:", value)
}

Thus, a map provides fast access to data by key with an amortized operation time close to O(1).