Checking if a List is Empty

Part of the Fundamentals section of Coddy's Dart journey — lesson 54 of 94.

The isEmpty and isNotEmpty properties let you check if a list contains any elements. These properties return boolean values.

Create a list of numbers:

List<int> numbers = [1, 2, 3];
bool hasElements = !numbers.isEmpty;
print('List has elements: $hasElements');

After executing the above code, the output will be:

List has elements: true

Create an empty list and check if it's empty:

List<String> emptyList = [];
bool isEmpty = emptyList.isEmpty;
print('List is empty: $isEmpty');

After executing the above code, the output will be:

List is empty: true

You can also use the isNotEmpty property:

bool hasItems = numbers.isNotEmpty;
print('List has items: $hasItems');

After executing the above code, the output will be:

List has items: true

Challenge

Beginner

In this challenge, you'll practice checking if a list is empty in Dart. You can use the isEmpty property to check if a list contains no elements.

Complete the code below to check if the shoppingList is empty. If it is empty, set the message variable to "Your shopping list is empty!"; otherwise, set it to "You have items in your shopping list!"

Expected output:

Your shopping list is empty!

Cheat sheet

Use isEmpty and isNotEmpty properties to check if a list contains elements. These properties return boolean values.

Check if a list is empty:

List<String> emptyList = [];
bool isEmpty = emptyList.isEmpty;
print('List is empty: $isEmpty'); // List is empty: true

Check if a list has elements:

List<int> numbers = [1, 2, 3];
bool hasItems = numbers.isNotEmpty;
print('List has items: $hasItems'); // List has items: true

Alternative way using negation:

bool hasElements = !numbers.isEmpty;

Try it yourself

void main() {
  // This shopping list is already defined for you
  List<String> shoppingList = [];
  
  // TODO: Check if the shoppingList is empty
  // If it is empty, set message to "Your shopping list is empty!"
  // Otherwise, set message to "You have items in your shopping list!"
  String message = "";
  
  // This will display the result
  print(message);
}