Why maps are used in Go - See It in Action

Why maps are used

📖 Scenario: Imagine you run a small library. You want to keep track of how many copies of each book you have. You need a way to quickly find the number of copies by the book's title.

🎯 Goal: You will create a map in Go to store book titles as keys and their copy counts as values. Then you will look up and print the number of copies for a specific book.

📋 What You'll Learn

Create a map with string keys and int values

Add at least three books with their copy counts

Create a variable to hold the title to look up

Use the map to find the copy count for that title

Print the result

💡 Why This Matters

🌍 Real World

Libraries, stores, and many apps use maps to quickly find information by a name or ID.

💼 Career

Understanding maps is important for programming jobs that handle data lookup, caching, and fast access.

1

Create a map of books and their copy counts

Create a map called library with string keys and int values. Add these entries exactly: "Go Programming": 5, "Python Basics": 3, "Java Fundamentals": 4.

Go

// Create the map called library with the given books and counts
// Your code here

Hint

Use map[string]int{} to create the map with string keys and int values.

2

Create a variable for the book title to look up

Create a string variable called bookTitle and set it to "Python Basics".

Go

library := map[string]int{"Go Programming": 5, "Python Basics": 3, "Java Fundamentals": 4}
// Create the variable bookTitle with value "Python Basics"
// Your code here

Hint

Use bookTitle := "Python Basics" to create the variable.

3

Look up the copy count for the book title

Create an int variable called copies and set it to the value from library for the key bookTitle.

Go

library := map[string]int{"Go Programming": 5, "Python Basics": 3, "Java Fundamentals": 4}
bookTitle := "Python Basics"
// Get the number of copies for bookTitle from library and store in copies
// Your code here

Hint

Use copies := library[bookTitle] to get the value from the map.

4

Print the number of copies for the book

Use fmt.Println to print the text "Copies of Python Basics:" followed by the value of copies.

Go

package main

import "fmt"

func main() {
    library := map[string]int{"Go Programming": 5, "Python Basics": 3, "Java Fundamentals": 4}
    bookTitle := "Python Basics"
    copies := library[bookTitle]
    // Print the number of copies with a message
    // Your code here
}

Hint

Use fmt.Println("Copies of Python Basics:", copies) to print the message and value.