Maps (Key-Value Pairs)

Key map properties include:

• make(): Maps must be initialized using the `make()` function or a map literal. Writing values to an uninitialized (nil) map causes a runtime panic.
• Comma-OK Idiom: Accessing a non-existent key in a Go map returns its zero value without error. To verify whether a key actually exists, use the **comma-ok** assignment syntax: `val, ok := scores["Alice"]`. If `ok` is true, the key exists.

Let's run a program declaring maps, inserting items, and verifying keys using the comma-ok idiom:

package main

import "fmt"

func main() {
    // Initialize map using make
    scores := make(map[string]int)

    scores["Alice"] = 95
    scores["Bob"] = 88

    fmt.Println("Scores Map: ", scores)

    // Comma-ok verification
    val, ok := scores["Charlie"]
    if ok {
        fmt.Printf("Charlie's score: %d\n", val)
    } else {
        fmt.Println("Charlie's score does not exist in the map!")
    }

    // Delete key
    delete(scores, "Bob")
    fmt.Println("After deleting Bob: ", scores)
}