例題.2次元配列をflatten（reduceを使う）

Python

py

reduce(lambda a, e: a + e, items)

py

items = [[1, 2], [3, 4, 5], [6, 7]]
items_f = reduce(lambda a, e: a + e, items)

C#

cs

items.Aggregate((a, e) => Enumerable.Concat(a, e).ToList() );