How can you filter an array of strings names to include only those starting with the letter 'J' and convert them to uppercase in one line?

hard📝 Application Q9 of 15

Ruby - Enumerable and Collection Processing

How can you filter an array of strings names to include only those starting with the letter 'J' and convert them to uppercase in one line?

Anames.map(&:upcase).select { |n| n.start_with?("J") }

Bnames.filter { |n| n.upcase.start_with?("J") }

Cnames.select { |n| n.start_with?("J") }.map(&:upcase)

Dnames.select(&:upcase).filter { |n| n.start_with?("J") }

Step-by-Step Solution

Solution:

Step 1: Filter names starting with 'J'
Use select { |n| n.start_with?("J") } to keep only names starting with 'J'.
Step 2: Convert filtered names to uppercase
Chain map(&:upcase) to convert each selected name to uppercase.
Final Answer:
names.select { |n| n.start_with?("J") }.map(&:upcase) -> Option C
Quick Check:
Filter then map for transformation [OK]

Quick Trick: Chain select then map for filter + transform [OK]

Common Mistakes:

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