Understanding Go Maps

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Understanding Go Maps

Maps in Go are unordered key-value data structures. They are created using the built-in `map` keyword with syntax `map[KeyType]ValueType`. You can add entries using bracket notation, check for existence using the comma-ok idiom, delete entries with the `delete()` function, and iterate over all entries with `range`. Maps return the zero value for missing keys.

snippet.go
go
package main
 
import "fmt"
 
func main() {
    scores := map[string]int{
        "Alice":   95,
        "Bob":     87,
        "Charlie": 92,
    }
 
    scores["Diana"] = 88
 
    if score, exists := scores["Bob"]; exists {
        fmt.Printf("Bob's score: %d\n", score)
    }
 
    delete(scores, "Charlie")
 
    for name, score := range scores {
        fmt.Printf("%s: %d\n", name, score)
    }
}

Breakdown

scores := map[string]int{

Declares a map with string keys and int values

"Alice": 95,

Initializes with three key-value pairs

scores["Diana"] = 88

Adds a new entry to the map

if score, exists := scores["Bob"]; exists {

Comma-ok idiom checks if key exists and retrieves value

delete(scores, "Charlie")

Removes an entry from the map

for name, score := range scores {

Iterates over all key-value pairs

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Understanding Go Maps

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