Sorting the NSDictionary Using Bubble Sort

leothenerd 10:58 pm on December 19, 2009 | Answers: 1    
Tags: bubble (2), nsdictionary (4), sort (4)

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• leothenerd 11:04 pm on December 19, 2009
  

  
  -(NSMutableArray*)bubbleSortDictionaryByKeys:(NSDictionary*)dict
  {
    //this method takes an NSDictionary and performs a basic bubblesort
    //on its keys. It then returns those ordered keys as an NSMutableArray.
    //You can then traverse the original NSDictionary and retrive its
    //ordered objects by simply stepping through each key in the NSMutableArray.
  
    if(!dict)
      return nil;
    NSMutableArray *sortedKeys = [NSMutableArray arrayWithArray: [dict allKeys]];
     if([sortedKeys count] <= 0)
      return nil;
    else if([sortedKeys count] == 1)
      return sortedKeys; //no sort needed
  
    //perform bubble sort on keys:
    int n = [sortedKeys count] -1;
    int i;
    BOOL swapped = YES;
  
    NSString *key1,*key2;
    NSComparisonResult result;
  
    while(swapped)
    {
      swapped = NO;
      for(i=0;i<n;i++)
      {
      key1 = [sortedKeys objectAtIndex: i];
      key2 = [sortedKeys objectAtIndex: i+1];
  
      //here is where we do our basic NSString comparison
      //This can be easily customized.
      //See the options for -compare: in NSString docs
      result = [key1 compare: key2 options: NSCaseInsensitiveSearch];
      if(result == NSOrderedDescending)
      {
      //we retain for good form, but these
      //objects should still be safely
      //retained by the dictionary:
      [key1 retain];
      [key2 retain];
  
      //pop the two keys out of the array
      [sortedKeys removeObjectAtIndex: i]; // key1
      [sortedKeys removeObjectAtIndex: i]; // key2
      //replace them
      [sortedKeys insertObject: key1 atIndex: i];
      [sortedKeys insertObject: key2 atIndex: i];
  
      [key1 release];
      [key2 release];
  
      swapped = YES;
        }
      }
    }
  
    return sortedKeys;
  }