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josephchang10/shuffle.m

Created April 18, 2017 10:25
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How to shuffle a NSMutableArray [Objective-C]
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shuffle.m
/* myArray is a NSMutableArray with some objects */
NSUInteger count = [myArray count];
for (NSUInteger i = 0; i < count; ++i) {
int nElements = count - i;
int n = (arc4random() % nElements) + i;
[myArray exchangeObjectAtIndex:i withObjectAtIndex:n];
}
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The Objective-C NSArray object doesn’t have a specific function to shuffle the elements of the array.

With this simple code we can shuffle one NSMutableArray randomly. We will use the exchangeObjectAtIndex method for exchange items within the array and arc4random to get a random number we use to exchange items.

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