Accessing Map Values

Part of the Fundamentals section of Coddy's GO journey — lesson 88 of 109.

To retrieve values from a map, use the key in square brackets. Go also provides a way to check if a key exists.

Create a map of student scores:

students := map[string]int{
    "Emma": 92,
    "Jack": 78,
}

// Access a value using its key
emmaScore := students["Emma"]
fmt.Println("Emma's score:", emmaScore)

Result:

Emma's score: 92

Check if a key exists using the two-value assignment:

score, exists := students["Alex"]
fmt.Println("Score:", score, "Exists:", exists)

Result:

Score: 0 Exists: false

Challenge

Beginner

In this challenge, you'll practice accessing values from a map in Go. A map of student grades has been created for you. Your task is to access and print the grade for a specific student.

The map contains student names as keys and their grades as values. You need to retrieve and print the grade for the student named 'Emma'.

Cheat sheet

To retrieve values from a map, use the key in square brackets:

students := map[string]int{
    "Emma": 92,
    "Jack": 78,
}

// Access a value using its key
emmaScore := students["Emma"]
fmt.Println("Emma's score:", emmaScore)

Check if a key exists using the two-value assignment:

score, exists := students["Alex"]
fmt.Println("Score:", score, "Exists:", exists)
// Output: Score: 0 Exists: false

Try it yourself

package main

import "fmt"

func main() {
	// A map of student grades
	studentGrades := map[string]string{
		"John":  "B+",
		"Emma":  "A-",
		"Sarah": "A",
		"Mike":  "C",
	}
	
	// TODO: Access and store Emma's grade in a variable called emmaGrade
	
	// TODO: Print Emma's grade with a message like: "Emma's grade is: A-"
	
}