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Shuffle NSMutableArray objective-c [duplicate]

This question already has answers here: Closed 11 years ago.

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What's t开发者_如何转开发he Best Way to Shuffle an NSMutableArray?

Non repeating random numbers

How to get random indexes of NSMutableArray without repeating? I have NSMutableArray *audioList. I want to play each track in shuffle mode, without repeating. How to do this in the best way?


See the code below:

int length = 10; // int length = [yourArray count];
NSMutableArray *indexes = [[NSMutableArray alloc] initWithCapacity:length];
for (int i=0; i<10; i++) [indexes addObject:[NSNumber numberWithInt:i]];
NSMutableArray *shuffle = [[NSMutableArray alloc] initWithCapacity:length];
while ([indexes count])
{
    int index = rand()%[indexes count];
    [shuffle addObject:[indexes objectAtIndex:index]];
    [indexes removeObjectAtIndex:index];
}
[indexes release];
for (int i=0; i<[shuffle count]; i++)
    NSLog(@"%@", [shuffle objectAtIndex:i]);

Now in shuffle you will have indexes of your array without repeating.

Hope, this will help you


Nekto's answer is great, but I would change two things:

1) Instead of using rand(), use arc4random() for less predictable results (more details here):

int index = arc4random() % [indexes count];

2) To output contents of "shuffle", use [myArray description] (no need to use a for loop):

NSLog(@"shuffle array: %@", [shuffle description]);
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