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rubyinfinitylazy-sequences

Do something infinitely many times with an index

In more ruby way of doing project euler #2 , part of the code is

while((v = fib(i)) < 4_000_000)
  s+=v if v%2==0
  i+=1
end

Is there a way to change i += 1 into a more functional programming style construct?

The best I can think of is

Float::MAX.to_i.times do |i|
  v = fib(i)
  break unless v < 4_000_000
  s += v if v%2==0
end

because you can't call .times on a floating point number.

Solution

  • Numeric.step has default parameters of infinity (the limit) and 1 (the step size).

    1.step do |i|
  #...
end

    For fun, you might even want to try

    1.step.size