3 replies to this topic

[boboc]

am si eu o intrebare,cum pot sorta un NSArray ale carui elemente sunt cheile(NSString) dintr-un NSDictionary?
am incercat medota keysSortedByValueUsingSelector dar imi pune cheile in array nesortate.

array = [dictionary keysSortedByValueUsingSelector: @selector (compare:)];

Si as mai avea o problema dintr-o carte,tot un array dar NSMutableArray ale carui elemnte sunt fractii(obiecte).
Am incercat asa dar nu merge:

[array sortUsingSelector: @selector(compareFractions:)];

- NSCoparisonResult compareFractions: (id) f
{
	return [(numerator/denominator) compare: (f.numerator/f.denominator)];
}

Multumesc anticipat.

[raducul]

NSSortDescriptor *__sd = [[[NSSortDescriptor alloc] initWithKey:@"name" ascending:TRUE] autorelease];
[__arr sortedArrayUsingDescriptors:[NSArray arrayWithObject:__sd]];

[boboc]

multumesc pentru raspuns.
nu vreau sa folosesc alta clasa,ma intereseaza de ce nu functioneaza metodele keysSortedByValueUsingSelector: si sortUsingSelector:

[boboc]

Am rezolvat ambele problema cu putina atentie
Metoda keysSortedByValueUsingSelector: returneaza un NSArray cu keys-urile iar metoda sortUsingSelector merge cu NSMutableArray si nu cu NSArray.
Trebuia sa folosesc metoda sortedArrayUsingSelector care are forma:

-(NSArray *) sortedArrayUsingSelector: (SEL) selector
array = [array sortedArrayUsing: @selector(compare:)];

Pentru celalalta problema,pentru a sorta un array cu fractii(obiecte) metoda care merge am facut-o asa:

[array sortUsingSelector: @selector(compareFractions:)];

-(NSComparisonResult) compareFractions: (Fraction *) f
{
    int first,second;
    first = numerator * f.denominator;
    second = f.numerator * denominator;
    if(first < second)
        return NSOrderedAscending;
    else if(first == second)
        return NSOrderedSame;
    else
        return NSOrderedDescending;
}

Edited by boboc, 22 April 2010 - 20:44.