CODEWITHSUNDEEP
objective-csortingnsmutablearraynsarray
GameDevGuru
GameDevGuru

Reputation: 1135

How can i count and sort a NSMutableArray duplicate values

I've seen this question:
NSMutableArray counting occurances of objects and then re-arange the array

The solution comes very close to what i need.

The solution I'm referring to:

NSInteger countedSort(id obj1, id obj2, void *context) {
   NSCountedSet *countedSet = context;
   NSUInteger obj1Count = [countedSet countForObject:obj1];
   NSUInteger obj2Count = [countedSet countForObject:obj2];

   if (obj1Count > obj2Count) return NSOrderedAscending;
   else if (obj1Count < obj2Count) return NSOrderedDescending;
   return NSOrderedSame;
}

and:

NSMutableArray *array = …;

NSCountedSet *countedSet = [[[NSCountedSet alloc] initWithArray:array]
autorelease];

[array sortUsingFunction:countedSort context:countedSet];

The sort returns proper sorted array by count, but i need the count either included or in another array sorted ascending.

Upvotes: 1

Views: 738

Answers (2)

Damien Romito
Damien Romito

Reputation: 10065

This return a sorted array ordered by the most occurring value

NSCountedSet *countedSet = [[NSCountedSet alloc] initWithArray:array];

NSArray *sortedValues = [countedSet.allObjects sortedArrayUsingComparator:^(id obj1, id obj2) {
    NSUInteger n = [countedSet countForObject:obj1];
    NSUInteger m = [countedSet countForObject:obj2];
    return (n <= m)? (n < m)? NSOrderedDescending : NSOrderedSame : NSOrderedAscending;
}];

Upvotes: 0

Ramy Al Zuhouri
Ramy Al Zuhouri

Reputation: 21986

A solution could be to simply query the counted set for the count of any object, to build an array that keep track of the counts: 

// This after having sorted the array:
NSMutableArray* counts= [NSMutableArray arrayWithCapacity: array.count];
for(id object in array) {
    [counts addObject: @([countedSet countForObject: object]) ];
}

Upvotes: 1

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