From: Michael Ulm <michael.ulm@...>
Date: 2005-12-07T00:06:23+09:00
Subject: Re: Shuffling an array, sort_by{rand}'s bias (was Re: need some Ruby

Uwe Schmitt wrote:

> || arr.sort_by{rand}
> 
> that is not equivalent to my solution.
> the python equivalent to yours is
> 
>   arr.sort(key = lambda x: random())
> 
> || 
> || > In Python it is quite easy by using list comprehensions...
> || What does that look like in Python? 
> 
> from random import random
> 
> def shuffle(a):
>     b = [ (random(), i) for i in a]
>     b.sort()
>     return [ x[1] for x in b ]
> 
> print shuffle(range(10))
> 

I would have thought those two functions do the same thing
with the exception that shuffle does not sort in place.
I'm probably missing something obvious. Could you explain
the difference between the two versions?

Michael

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Michael Ulm
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