標題: [Ruby] Fibonacci 數列.... [打印本頁]

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作者: weiye    時間: 2006-3-5 23:13     標題: [Ruby] Fibonacci 數列....

新聞群組： comp.lang.ruby
"Peter Ertl" <p...@gmx.org>
日期： Thu, 15 Dec 2005 03:16:29 +0900
主旨： ruby beats them all


that why I love ruby (and functional languages in general)

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代碼:

def fibonacci(n)
  a, b = 1, 1
  n.times do
    a, b = b, a + b
  end
  a
end

elegance beats ignorance (ruby vs. java)

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Christian Neukirchen <chneukirc...@gmail.com>
日期：Thu, 15 Dec 2005 04:27:08 +0900

That's not functional...

How about really doing it functional?

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代碼:

def fib(n)
  (1..n-2).inject([1, 1]) { |(a, b), n| [b, a+b] }.last
end

:)

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Edward Faulkner <e...@alum.mit.edu>
日期： Thu, 15 Dec 2005 04:58:15 +0900

If we're talking about elegance, I prefer this one.  It reads just
like the definition of the sequence:

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代碼:

def fib(n)
    n > 1 ? fib(n-1) + fib(n-2) : n
end

You can even make it run efficiently by memoizing it.  :-)


-Ed

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"Andrew Backer" <awbac...@gmail.com>
日期： 14 Dec 2005 22:37:43 -0800

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代碼:

def calc_iterative(n)
        a = [0,1,0]
        for i in 2..n
                a[k] = a[k-1] + a[k-2]
        end
        return a[n%3]
end

I like this one, since it uses array wrapping.  So many ways to write
it that are all *slightly*  different... But this was to show someone,
so :)

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