How to shuffle NSMutableArray without repetition

Question

Possible Duplicate:
What’s the Best Way to Shuffle an NSMutableArray?

Here in my code I want to shuffle the elements in the array and try to print it out, but it's not shuffling properly, I tried what is shown here.Its working but,it values are repating.

for(UIView *view in self.view.subviews)
{
    if([view isKindOfClass:[UIButton class]])
    { 
        button= (UIButton *)view;
        if (button.tag >=1 && button.tag <=20)
        {
            for (NSUInteger i = 0; i < count; ++i)
            {
                [texts rotate];
                // Select a random element between i and end of array to swap with.
                int nElements = count - i;
                int n = (arc4random() % nElements) + i;
                [texts exchangeObjectAtIndex:i withObjectAtIndex:n];
                //int myTag= j+1;
                //button = [self.view viewWithTag:myTag];
                name=[NSString stringWithFormat:@"%@",[texts objectAtIndex:n]];
                [button setTitle:name forState:UIControlStateNormal];
                NSLog(@"current  name :%@",name);

            }
        }

    }

}

After shuffling the array values are repeating,pls help me to solve this issue

… and [iphone - nsarray/nsmutablearray - re-arrange in random order](http://stackoverflow.com/questions/4202102/iphone-nsarray-nsmutablearray-re-arrange-in-random-order). — rob mayoff, Nov 03 '12 at 06:00
… and [how to randomize an NSMutableArray](http://stackoverflow.com/questions/6255369/how-to-randomize-an-nsmutablearray). — rob mayoff, Nov 03 '12 at 06:00
If you don't think any of those solves your problem, please edit your post to explain exactly what you're seeing that you think is incorrect output. — rob mayoff, Nov 03 '12 at 06:03
Adding the error to the question might give people a better idea of the problem. — 8vius, Nov 03 '12 at 06:16
Instead of if(button.tag == 1||button.tag == 2||..||button.tag == 20), why cant you use if (button.tag >=1 && button.tag <=20)? Short and simple. Easy to understand. Also what exactly is the error with above code? — iDev, Nov 03 '12 at 06:55
@ACB i update the code in my question, here now the probem problem is repeatation of array contents — Fazil, Nov 03 '12 at 07:55
So my understanding is that you want to shuffle texts once and then assign the objects in that shuffled array to the buttons in self.view subviews, right? And you dont want to have buttons having same name and it should be unique. is that correct? — iDev, Nov 03 '12 at 08:56
Raise it as a new question. It is not exactly about shuffling the array. Your problem is that button names are repeating. I think due to the question title, they have closed it. — iDev, Nov 05 '12 at 05:39
@ACB here i detailed http://stackoverflow.com/questions/13227350/shuffle-nsmutablearray-without-repeatation-and-showing-in-a-uibutton pls try to get me the solution yaar — Fazil, Nov 05 '12 at 06:57

score 0 · Answer 1 · answered Nov 03 '12 at 06:07

0

Try this int n = (arc4random() % count);
instead of
int n = (arc4random() % nElements) + i;

Ensure that you are swapping current element with any element in the texts instead of an element which is always succeeding it.

answered Nov 03 '12 at 06:07

Srinivas

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score 0 · Answer 2 · answered Nov 03 '12 at 06:12

Just make the category of NSMutableArray

@implementation NSMutableArray (ArrayUtils)
-(void)shuffle
{
static BOOL seeded = NO;
 if(!seeded)
{
    seeded = YES;
    srandom(time(NULL));
}

NSUInteger count = [self count];
for (NSUInteger i = 0; i < count; ++i) {
    // Select a random element between i and end of array to swap with.
    int nElements = count - i;
    int n = (random() % nElements) + i;
    [self exchangeObjectAtIndex:i withObjectAtIndex:n];
}

}

NSMutableArary *arr = [NSMutableArray alloc]init]; [arr shuffle]; its easy — SachinVsSachin, Nov 03 '12 at 06:27

How to shuffle NSMutableArray without repetition

2 Answers2

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