Sorting an Array with Strings that contains Numbers [duplicate]

Question

Possible Duplicate:
Sorting NSString values as if NSInteger using NSSortDescriptor

I have an Array that I fill with my NSMutableDictionary.. and I use this:

myArray =[[myDict allKeys]sortedArrayUsingSelector:@selector(IDONTKNOW:)];

AllKeys of myDicts are NSStrings... like 123.423 or 423.343... I need to sort the new myArray by incremental numbers.. 12.234 45.3343 522.533 5432.66 etc etc

What must insert in @selector to do this properly? Thanks

Answer 1

You can use an NSSortDescriptor and pass doubleValue as the key.

//sfloats would be your [myDict allKeys]
NSArray *sfloats = @[ @"192.5235", @"235.4362", @"3.235", @"500.235", @"219.72" ];
NSArray *myArray = [sfloats sortedArrayUsingDescriptors:
                    @[[NSSortDescriptor sortDescriptorWithKey:@"doubleValue" 
                                                    ascending:YES]]];

NSLog(@"Sorted: %@", myArray);

Answer 2

You can't direclty use sortedArrayUsingSelector:. Use sortedArrayUsingComparator: and implement a comparison block yourself.

Kinda like this q/a:

Changing the sort order of -[NSArray sortedArrayUsingComparator:]

(In fact, that Question's code can likely be copy/pasted into your code and it'll "just work" once you change it from integerValue to doubleValue for the four convert-string-to-number calls):

NSArray *sortedArray = [array sortedArrayUsingComparator: ^(id obj1, id obj2) {
    double n1 = [obj1 doubleValue];
    double n2 = [obj2 doubleValue];
    if (n1 > n2) {
        return (NSComparisonResult)NSOrderedDescending;
    }

    if (n1 < n2) {
        return (NSComparisonResult)NSOrderedAscending;
    }

    return (NSComparisonResult)NSOrderedSame;
}];