以随机顺序重新排列NSArray/MSMutableArray

Question

我正在使用NSArray/NSMutable数组来存储不同的对象.一旦添加了所有对象,我想以随机顺序重新排列它们.我该怎么做？

Answer 1

NSUInteger count = [yourMutableArray 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 = (arc4random() % nElements) + i;
   [yourMutableArray exchangeObjectAtIndex:i withObjectAtIndex:n];
}

Answer 2

// the Knuth shuffle
for (NSInteger i = array.count-1; i > 0; i--)
{
    [array exchangeObjectAtIndex:i withObjectAtIndex:arc4random_uniform(i+1)];
}