Zip for combining sequences in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the zip function do in Swift?

It combines two sequences into a single sequence of pairs, where each pair contains one element from each sequence at the same position.

beginner

How does zip handle sequences of different lengths?

The resulting zipped sequence stops as soon as the shortest input sequence runs out of elements.

beginner

Show a simple example of using zip with two arrays in Swift.

Example:<br><pre>let numbers = [1, 2, 3]
let letters = ["a", "b", "c"]
for pair in zip(numbers, letters) {
  print(pair)
}</pre><br>This prints:<br>(1, "a")<br>(2, "b")<br>(3, "c")

intermediate

Can you use zip with sequences other than arrays?

Yes, zip works with any sequences, such as arrays, ranges, or strings, as long as they conform to the Sequence protocol.

intermediate

What type does zip return in Swift?

It returns a Zip2Sequence which is a sequence of pairs (tuples) combining elements from the two input sequences.

What happens if you zip an array of 3 elements with an array of 5 elements?

A The zipped sequence has 3 pairs.

B The zipped sequence has 5 pairs.

C The zipped sequence has 8 pairs.

D It causes a runtime error.

Zip stops at the shortest sequence length, so the result has 3 pairs.

Which Swift protocol must sequences conform to for zip to work?

A Collection

B IteratorProtocol

C Equatable

D Sequence

zip works with any type conforming to the Sequence protocol.

What is the type of each element inside the zipped sequence?

A Array

B Tuple

C Dictionary

D Set

Each element is a tuple containing one element from each input sequence.

How do you access the first element of a pair from zip?

A pair.0

B pair[0]

C pair.first

D pair.getFirst()

Tuples use dot notation with index numbers, so pair.0 accesses the first element.

Which of these is a valid use of zip in Swift?

A zip([1,2,3], 5)

B zip([1,2], "ab")

C zip(1...3, ["a", "b", "c"])

D zip("abc", 123)

You can zip any two sequences, such as a range and an array.

Explain how the zip function combines two sequences in Swift and what happens if they have different lengths.

Think about pairing items like matching socks from two drawers.

Write a short Swift code snippet using zip to combine two arrays and print each pair.

Use a for-in loop to iterate over zipped sequences.