NSDictionary keys sorted by value numerically?

Question

I store names as keys and scores as values into an NSDictionary for saving in NSUserDefaults. I then want to get back the keys sorted by score, but I can't seem to sort them numerically, only by string. The result of 100, 50, 300, 200, 500 for example would be 100, 200, 300, 50, 500

Can this be done or do I need to go about this differently?

NSString *defaultNames[] = {@"Matt", @"Terry",@"Jessica",@"Sean",nil};
NSNumber *defaultScores[] = {@"600", @"500",@"100",@"50", nil};

NSDictionary *newScoreDict =  [NSDictionary dictionaryWithObjects:(id *)defaultScores forKeys:(id *)defaultNames count:7];

NSArray *currScores = [scoreDict keysSortedByValueUsingSelector:@selector(compare:)];

Answer 1

http://developer.apple.com/mac/library/DOCUMENTATION/Cocoa/Reference/Foundation/Classes/NSString%5FClass/Reference/NSString.html#//apple%5Fref/doc/uid/20000154-intValue

Answer 2

-compare: is a string compare. Pass a different method for the comparison, e.g:

@implementation NSString (numericComparison)

- (NSComparisonResult) compareNumerically:(NSString *) other
{
float myValue = [self floatValue];
float otherValue = [other floatValue];
if (myValue == otherValue) return NSOrderedSame;
return (myValue < otherValue ? NSOrderedAscending : NSOrderedDescending);
}

@end

In your specific case, you could use -intValue instead.

Answer 3

Not sure it would help, but you can also save an NSArray in a plist; unlike an NSDictionary (which returns keys in essentially random order), you get them back as you put them in.

Answer 4

how about using keysSortedByValueUsingSelector (NSDictionary)

Seems to be what you need as per the documentation in XCode

Answer 5

@implementation NSString (numericComparison)

- (NSComparisonResult) floatCompare:(NSString *) other
{
    float myValue = [self floatValue];
    float otherValue = [other floatValue];
    if (myValue == otherValue) return NSOrderedSame;
    return (myValue < otherValue ? NSOrderedAscending : NSOrderedDescending);
}

- (NSComparisonResult) intCompare:(NSString *) other
{
    int myValue = [self intValue];
    int otherValue = [other intValue];
    if (myValue == otherValue) return NSOrderedSame;
    return (myValue < otherValue ? NSOrderedAscending : NSOrderedDescending);
}

@end

NSString *defaultNames[] = {@"Matt", @"Terry",@"Jessica",@"Sean",nil};
// NSNumber *defaultScores[] = {@"600", @"500",@"100",@"50", nil};

NSNumber *defaultScores[] = {                                                                   
            [NSNumber  numberWithInt:600],
            [NSNumber  numberWithInt:500],
            [NSNumber  numberWithInt:100],
            [NSNumber  numberWithInt:50],
            nil 
    };

NSDictionary *newScoreDict =  [NSDictionary dictionaryWithObjects:(id *)defaultScores forKeys:(id *)defaultNames count:4];

NSArray *currScores = [newScoreDict keysSortedByValueUsingSelector:@selector(intCompare:NotSureWhatGoesHere:)];

I am still confused with the previous line ?

Do I just use

//
NSArray *currScores = [newScoreDict keysSortedByValueUsingSelector:@selector(intCompare:other:)];
//

Is the array of numbers OK, or is there an easier way ?

Thank You Very Much...

Answer 6

This worked perfect for me :

http://discussions.apple.com/thread.jspa?threadID=2356650&tstart=0

Thank You for the great forum...