iOS中的遍历（数组NSArray，字典NSDictionary，集合NSSet）

NSArray *keys = [dictionary allKeys];  
for (int i = 0; i < keys.count; i++)  {  
    NSLog(@"object = %@", dictionary[keys[i]]);  
}  


NSArray *objects = [set allObjects];     
for (int i = 0; i < objects.count; i++)  {  
   NSLog(@"object = %@", objects[i]);  
 }