Tuples for grouped values in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a tuple named 'person' with a name and age.

Swift

let person = ("John", [1])

Drag options to blanks, or click blank then click option'

A30

B"John"

Cnil

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string instead of a number for age.

Leaving the blank empty.

The tuple holds a name and an age. The age should be a number like 30.

2fill in blank

medium

Complete the code to access the first element of the tuple 'coordinates'.

Swift

let coordinates = (x: 10, y: 20)
let xValue = coordinates.[1]

Drag options to blanks, or click blank then click option'

Ay

Bx

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using the label 'y' instead of 'x'.

Using numeric indexes instead of labels.

To get the x value from the tuple, use the label 'x'.

3fill in blank

hard

Fix the error in the code by completing the tuple declaration correctly.

Swift

let result = (status: "OK", code: [1])

Drag options to blanks, or click blank then click option'

Anil

B"200"

Ctrue

D200

Attempts:

3 left

💡 Hint

Common Mistakes

Putting 200 in quotes, making it a string.

Using a boolean or nil instead of a number.

The code expects an integer for 'code', so use 200 without quotes.

4fill in blank

hard

Fill both blanks to create a tuple with named elements and access the second element.

Swift

let point = ([1]: 5, [2]: 10)
let yValue = point.y

Drag options to blanks, or click blank then click option'

Ax

Bz

Cy

Da

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong labels that don't match the access.

Mixing up the order of labels.

The tuple has labels 'x' and 'y'. We use 'y' to access the second element.

5fill in blank

hard

Fill all three blanks to create a tuple, access its elements, and print the name.

Swift

let person = ([1]: "Alice", [2]: 28)
let name = person.[3]
print(name)

Drag options to blanks, or click blank then click option'

Aname

Bage

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong labels that don't match the tuple.

Accessing 'age' instead of 'name' when printing.

The tuple has labels 'name' and 'age'. We access 'name' to print it.

Practice

1. What is a tuple in Swift used for?

easy

A. Defining a function

B. Creating a new class type

C. Grouping multiple values into a single compound value

D. Declaring a constant

Solution

1. Step 1: Understand tuple purpose

   Tuples combine multiple values into one grouped value without creating a new type.

2. Step 2: Compare with other options

   Classes, functions, and constants serve different purposes unrelated to grouping multiple values simply.

3. Final Answer:

   Grouping multiple values into a single compound value -> Option C

4. Quick Check:

   Tuple = grouped values [OK]

Hint: Tuples bundle values together simply [OK]

Common Mistakes:

• Confusing tuples with classes or structs
• Thinking tuples define functions
• Assuming tuples declare constants only

2. Which of the following is the correct syntax to declare a tuple with an Int and a String in Swift?

easy

A. let person: (Int, String) = (25, "Alice")

B. let person = Int, String = (25, "Alice")

C. let person = Int: 25, String: "Alice"

D. let person: Int, String = (25, "Alice")

Solution

1. Step 1: Check tuple declaration syntax

   Correct tuple syntax uses parentheses with types inside, then assigns values in parentheses.

2. Step 2: Validate each option

   let person: (Int, String) = (25, "Alice") correctly declares a tuple type and assigns matching values. Others have syntax errors or wrong format.

3. Final Answer:

   let person: (Int, String) = (25, "Alice") -> Option A

4. Quick Check:

   Tuple syntax = (Type1, Type2) = (value1, value2) [OK]

Hint: Use parentheses for tuple types and values [OK]

Common Mistakes:

• Omitting parentheses around types
• Trying to declare types outside tuple parentheses
• Using incorrect colon placement

3. What will be the output of this Swift code?

let coordinates = (x: 10, y: 20)
print(coordinates.x + coordinates.y)

medium

A. Error: Cannot access tuple elements by label

B. 10 20

C. coordinates.xcoordinates.y

D. 30

Solution

1. Step 1: Understand tuple with labels

   The tuple has labels x and y with values 10 and 20 respectively.

2. Step 2: Calculate the sum

   Adding coordinates.x (10) and coordinates.y (20) results in 30.

3. Final Answer:

   30 -> Option D

4. Quick Check:

   10 + 20 = 30 [OK]

Hint: Access tuple values by labels with dot notation [OK]

Common Mistakes:

• Trying to print tuple without accessing elements
• Confusing tuple labels with dictionary keys
• Assuming tuple elements can't be accessed by label

4. Identify the error in this Swift code snippet:

let person = (name: "Bob", age: 30)
print(person[0])

medium

A. Tuples cannot be accessed by index using square brackets

B. Tuple labels must be strings, not integers

C. Tuple elements must be accessed with parentheses, not brackets

D. The tuple declaration is missing type annotations

Solution

1. Step 1: Check tuple access method

   Tuples in Swift are accessed by position using dot and index (e.g., .0), not square brackets.

2. Step 2: Analyze the code error

   Using person[0] causes an error because square brackets are not valid for tuple indexing.

3. Final Answer:

   Tuples cannot be accessed by index using square brackets -> Option A

4. Quick Check:

   Use dot and number for tuple index, not brackets [OK]

Hint: Use dot and number for tuple index, not brackets [OK]

Common Mistakes:

• Using square brackets to access tuple elements
• Confusing tuples with arrays or dictionaries
• Assuming type annotations are mandatory for tuples

5. Given a function that returns a tuple with a person's name and age, how can you extract these values into separate variables?

func getPerson() -> (String, Int) {
    return ("Emma", 28)
}
// Extract values here

hard

A. let person = getPerson()
let personName = person[0]
let personAge = person[1]

B. let (personName, personAge) = getPerson()

C. let personName = getPerson().name
let personAge = getPerson().age

D. let personName, personAge = getPerson()

Solution

1. Step 1: Understand tuple unpacking

   Swift allows unpacking tuple return values directly into variables using parentheses.

2. Step 2: Evaluate options

   let (personName, personAge) = getPerson() correctly unpacks both values at once. let person = getPerson() let personName = person[0] let personAge = person[1] uses invalid indexing. let personName = getPerson().name let personAge = getPerson().age attempts to access nonexistent labels. let personName, personAge = getPerson() has invalid syntax.

3. Final Answer:

   let (personName, personAge) = getPerson() -> Option B

4. Quick Check:

   Tuple unpacking uses let (a, b) = tuple [OK]

Hint: Unpack tuples with let (a, b) = function() [OK]

Common Mistakes:

• Using square brackets to access tuple elements
• Attempting to access tuple elements by nonexistent labels
• Incorrect syntax for unpacking tuples