My original solution (Ruby)

a, b, sum = 1, -1, 0 while a <= 4_000_000 a, b = a+b, a sum += a if a.even? end sum # => 4613732

I also thought it would be fun to try it as a lazy enumerator, though I still like my original solution better.

a, b = 1, -1 loop.lazy .map { a, b = a+b, a; a } .take_while { |n| n <= 4_000_000 } .select(&:even?) .sum # => 4613732

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## re: Project Euler #2 - Even Fibonacci numbers VIEW POST

FULL DISCUSSIONMy original solution (Ruby)

I also thought it would be fun to try it as a lazy enumerator, though I still like my original solution better.