How can you use reject combined with map to get an array of squares of only odd numbers from nums = [1, 2, 3, 4, 5]?

hard📝 Application Q9 of 15

Ruby - Enumerable and Collection Processing

How can you use reject combined with map to get an array of squares of only odd numbers from nums = [1, 2, 3, 4, 5]?

Anums.reject(&:even?).map { |n| n * n }

Bnums.reject(&:odd?).map { |n| n * n }

Cnums.map { |n| n * n }.reject(&:odd?)

Dnums.map(&:odd?).reject { |n| n * n }

Step-by-Step Solution

Solution:

Step 1: Reject even numbers
Use reject(&:even?) to remove even numbers, keeping only odd numbers.
Step 2: Map remaining numbers to their squares
Use map { |n| n * n } to square each odd number.
Final Answer:
nums.reject(&:even?).map { |n| n * n } -> Option A
Quick Check:
Reject even, then map squares [OK]

Quick Trick: Reject even numbers first, then map squares [OK]

Common Mistakes:

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