I'm trying to sort an NSMutableArray of objects by a field of type double <p>the code I'm currently trying doesn't give any errors but after it runs nothing is sorted. This is my first time in objective-c so I'm hoping there's something obvious here that I'm missing.</p> <pre><code>NSSortDescriptor * sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"distanceOfPlace" ascending:true] ; [surroundingRestaurants sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]]; </code></pre>