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Access Map Elements in Go

Last Updated : May 27, 2025

In Go, you can access elements in a map using the key inside square brackets. If the key exists, the corresponding value is returned. If the key is not present, a zero value for the value type is returned.

Accessing Map Elements by Key

Use the key inside square brackets to retrieve a value from a map.

Example

This example shows how to access values using keys in a map:

package main
import "fmt"

func main() {
    countries := map[string]string{
        "IN": "India",
        "US": "United States",
        "FR": "France",
    }

    fmt.Println("IN:", countries["IN"])
    fmt.Println("US:", countries["US"])
    fmt.Println("FR:", countries["FR"])
}

When executed, this program outputs:

IN: India
US: United States
FR: France

Accessing a Non-Existing Key

If you try to access a key that doesn't exist, Go returns the zero value for the map's value type.

Example

This example attempts to access a non-existing key:

package main
import "fmt"

func main() {
    marks := map[string]int{
        "Rahul": 85,
        "Sneha": 92,
    }

    fmt.Println("Marks of Rahul:", marks["Rahul"])
    fmt.Println("Marks of Amit:", marks["Amit"]) // Key not present
}

When executed, this program outputs:

Marks of Rahul: 85
Marks of Amit: 0

Using Value with Existence Check

You can use the second return value to check if a key exists in the map.

Example

This example shows how to check if a key exists using the comma-ok idiom:

package main
import "fmt"

func main() {
    fruits := map[string]int{
        "Apple":  10,
        "Banana": 20,
    }

    qty, exists := fruits["Apple"]
    if exists {
        fmt.Println("Apple is available with quantity:", qty)
    }

    qty, exists = fruits["Mango"]
    if !exists {
        fmt.Println("Mango is not available")
    }
}

When executed, this program outputs:

Apple is available with quantity: 10
Mango is not available

Exercise

Select the correct answer for each question about accessing map elements in Go.

1. What is returned when you access a non-existent key in a map of type map[string]int? --Select-- 0 nil runtime error
2. How can you check if a key exists in a Go map? --Select-- value, ok := map[key] map.contains(key) exists(map, key)
3. What happens if you try to access a key in a nil map? --Select-- returns zero value compile-time error panics at runtime