Given arr = [2, 4, 6, 8, 10, 12], which expression returns a new array with every second element starting from index 1 up to index 5?

hard📝 Application Q15 of 15

Ruby - Arrays

Given arr = [2, 4, 6, 8, 10, 12], which expression returns a new array with every second element starting from index 1 up to index 5?

Aarr[1..5].select.with_index { |_, i| i.even? }

Barr[1..5].select.with_index { |_, i| i.odd? }

Carr[1...6].values_at(*arr[1...6].each_index.select(&:even?))

Darr[1..5].values_at(*arr[1..5].each_index.select(&:odd?))

Step-by-Step Solution

Solution:

Step 1: Slice array from index 1 to 5
arr[1..5] gives [4, 6, 8, 10, 12].
Step 2: Select every second element starting from index 1 of the slice
Indexes inside the slice are 0 to 4. Selecting odd indexes (1, 3) gives elements 6 and 10.
Step 3: Check options for correct syntax and output
arr[1..5].values_at(*arr[1..5].each_index.select(&:odd?)) uses values_at with odd indexes on the slice correctly, returning [6, 10].
Final Answer:
arr[1..5].values_at(*arr[1..5].each_index.select(&:odd?)) -> Option D
Quick Check:
Use values_at with odd indexes on slice for every second element [OK]

Quick Trick: Use values_at with selected indexes for custom slicing [OK]

Common Mistakes:

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