selective_flatten

📦 Selective Depth Flattening with flat_map and flatten

Use flat_map to map and flatten one level in a single pass, then call flatten(depth) for deeper levels. This two-step approach avoids unnecessary deep flattening and keeps your intentions clear. Ideal for nested list processing where only certain levels need merging.

data = [[1, [2, 3]], [4, [5, [6]]]]
# Flatten one level after mapping:
step1 = data.flat_map { |a, b| [a, b] }
# => [1, [2,3], 4, [5,[6]]]

# Then flatten just one more level:
result = step1.flatten(1)
# => [1, 2, 3, 4, 5, [6]]