[Solved] What will be the output of this Ruby code? arr = [[2, 3], [4, 5]] result = arr.flat_map { |sub| sub.select { |x| x.odd? } } puts result.inspect | Ruby

Ruby - Enumerable and Collection Processing

What will be the output of this Ruby code?

arr = [[2, 3], [4, 5]]
result = arr.flat_map { |sub| sub.select { |x| x.odd? } }
puts result.inspect

A[3, 5]

B[2, 4]

C[[3], [5]]

D[2, 3, 4, 5]

Step-by-Step Solution

Solution:

Step 1: Analyze the block
The block uses select to filter odd numbers from each sub-array.
Step 2: Apply flat_map
flat_map applies the block to each sub-array and then flattens the results by one level.
Step 3: Evaluate each sub-array
From [2, 3], select odd numbers -> [3]; from [4, 5], select odd numbers -> [5].
Step 4: Flatten one level
Flattening [[3], [5]] results in [3, 5].
Final Answer:
[3, 5] -> Option A
Quick Check:
Filtering odds then flattening one level [OK]

Quick Trick: flat_map flattens after filtering each sub-array [OK]

Common Mistakes:

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