Re: Array of random, non-repeating numbers
Re: Array of random, non-repeating numbers
- Subject: Re: Array of random, non-repeating numbers
- From: "Michael Ash" <email@hidden>
- Date: Thu, 13 Jul 2006 12:39:23 -0400
On 7/13/06, Bobby B <email@hidden> wrote:
Hey guys,
I'm trying to write a way to generate a random array of X numbers, and
the numbers need to be between 0 and X, and not be repeating (its for
generating a random playlist.)
Just generate the random playlist directly, don't bother with indexes.
Put the tracks into an array, then use the canonical shuffle algorithm
which, in pseudocode, is:
for i from 0 to array_length - 2
random_index = random in [i, array_length - 1]
swap array[i] with array[random_index]
Transforming this into real code is left as an exercise for the reader.
If you really do need random numbers, fill an array with the numbers
sequentially and then run the shuffle routine on it.
The other responses in this thread (no offense meant, guys) work and
are unbiased, but are more complex and slower than necessary.
Mike
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Cocoa-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden