Is operator for type checking in Swift - Mini Project: Build & Apply

Is operator for type checking

📖 Scenario: Imagine you are building a simple app that handles different types of pets. You want to check the type of each pet to perform specific actions.

🎯 Goal: You will create a list of pets with different types, then use the is operator to check each pet's type and count how many pets are dogs.

📋 What You'll Learn

Create an array called pets containing different pet types

Create a variable called dogCount to count dogs

Use a for loop with is operator to check if a pet is a dog

Print the total number of dogs using print

💡 Why This Matters

🌍 Real World

Type checking helps apps handle different data safely, like distinguishing between pet types to show correct info.

💼 Career

Understanding type checking is important for Swift developers to write safe and bug-free code, especially when working with mixed data.

1

Create the pets array

Create an array called pets containing these exact values: "Dog", "Cat", "Dog", "Bird", "Dog".

Swift

# Create the pets array with the exact values
# Your code here

Need a hint?

Use square brackets [] to create an array and separate values with commas.

2

Create the dogCount variable

Create a variable called dogCount and set it to 0 to count the number of dogs.

Swift

let pets = ["Dog", "Cat", "Dog", "Bird", "Dog"]
# Create dogCount variable and set it to 0
# Your code here

Need a hint?

Use var to create a variable that can change.

3

Use the is operator to count dogs

Use a for loop with the variable pet to iterate over pets. Inside the loop, use the is operator to check if pet is String and equals "Dog". If yes, increase dogCount by 1.

Swift

let pets = ["Dog", "Cat", "Dog", "Bird", "Dog"]
var dogCount = 0
# Use a for loop and is operator to count dogs
# Your code here

Need a hint?

Use for pet in pets to loop. Use if pet is String && pet == "Dog" to check type and value.

4

Print the number of dogs

Write print("Number of dogs: \(dogCount)") to display the total number of dogs counted.

Swift

let pets = ["Dog", "Cat", "Dog", "Bird", "Dog"]
var dogCount = 0
for pet in pets {
    if pet is String && pet == "Dog" {
        dogCount += 1
    }
}
# Print the number of dogs
# Your code here

Need a hint?

Use print with string interpolation to show the count.