Ex 24: Set Comprehension Challenges

Problem​

Sets are powerful for ensuring uniqueness and performing mathematical-style operations. Complete the following four tasks using set comprehensions:

1. Vowel Extraction: From a sentence string, collect all unique vowels present.
2. Intersection: Given two lists, build a set of values that appear in BOTH (without using the & operator).
3. Length Set: From a list of words, build a set containing the unique lengths of those words.
4. Prime Filtering: From a list of numbers, build a set of only the prime numbers.

Rules​

• For Task 1, use the sentence: "the quick brown fox jumps over the lazy dog".
• For Task 2, use list_a = [1, 2, 3, 4, 5] and list_b = [3, 4, 5, 6, 7].
• For Task 3, use: ["cat", "elephant", "dog", "python", "owl", "snake", "rat"].
• For Task 4, use: [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13].

Boilerplate​

Copy below code and paste to our IDE for head start.

# Task 1: Vowels
sentence = "the quick brown fox jumps over the lazy dog"
unique_vowels = {} # Use a set comprehension

# Task 2: Intersection
list_a = [1, 2, 3, 4, 5]
list_b = [3, 4, 5, 6, 7]
common_elements = {}

# Task 3: Word Lengths
words = ["cat", "elephant", "dog", "python", "owl", "snake", "rat"]
unique_lengths = {}

# Task 4: Primes
numbers = [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]
prime_numbers = {}

Expected output​

Note: Set order is not guaranteed, but the values should match.

{'a', 'e', 'i', 'o', 'u'}
{3, 4, 5}
{3, 5, 6, 8}
{2, 3, 5, 7, 11, 13}

Solution​

Only view the solution after trying our best.

# 1. Vowels
sentence = "the quick brown fox jumps over the lazy dog"
unique_vowels = {char for char in sentence if char in "aeiou"}

# 2. Intersection
list_a = [1, 2, 3, 4, 5]
list_b = [3, 4, 5, 6, 7]
common_elements = {item for item in list_a if item in list_b}

# 3. Word Lengths
words = ["cat", "elephant", "dog", "python", "owl", "snake", "rat"]
unique_lengths = {len(word) for word in words}

# 4. Primes
numbers = [2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]
prime_numbers = {
    num for num in numbers
    if num > 1 and all(num % i != 0 for i in range(2, int(num**0.5) + 1))
}