Geek asks and answers

Sort NSMutableArray with custom objects by another NSMutableArray

I have 2 NSMutableArrays. The first array contains custom intables with a property NSString *itemID, the second array contains only from NSStringobjects with the same values itemID, but in a different order. I need to sort the first array by property itemIDfor each object, and it should be sorted as the second array.

How can i do this?

+5
source share
3 answers
guideArray = < YOUR SECOND ARRAY WITH STRING OBJECT >;    
unsortedArray = < YOUR FIRST ARRAY WITH CUSTOM OBJECT >;

[unsortedArray sortUsingComparator:^(id o1, id o2) {
    Items *item1 = o1;
    Items *item2 = o2;
    NSInteger idx1 = [guideArray indexOfObject:item1.ItemID];
    NSInteger idx2 = [guideArray indexOfObject:item2.ItemID];
    return idx1 - idx2;
}];
NSLog(@"%@",unsortedArray);
+3
source

Save user objects in the dictionary with the itemIDas key , use this dictionary as a search to sort objects:

    NSArray *objects; // your objects
    NSMutableArray *hintArray; // your sorted IDs
    NSMutableDictionary *lookupDict = [[NSMutableDictionary alloc] initWithCapacity:[objects count]];
    NSMutableArray *sortedObjects = [[NSMutableArray alloc] initWithCapacity:[hintArray count]];

    for (id object in objects) {
        [lookupDict setValue:object forKey:[object itemID]];
    }

    for (id hint in hintArray) {
        [sortedObjects addObject:[lookupDict valueForKey:hint]];
    }

EDIT: inplace sort objects:

    NSMutableArray *objects;
    NSMutableArray *hintArray;
    NSMutableDictionary *lookupDict = [[NSMutableDictionary alloc] initWithCapacity:[hintArray count]];

    int i = 0;
    for (NSString *itemID in hintArray) {
        [lookupDict setValue:[NSNumber numberWithInt:i] forKey:itemID];
        i++;
    }

    [objects sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        return [[lookupDict valueForKey:[obj1 itemID]] compare:[lookupDict valueForKey:[obj2 itemID]]];
    }];
+1

You can compare your two objects using the following syntax: -

[items sortUsingComparator:^NSComparisonResult(Attribute *obj1, Attribute *obj2) 
{
    return [[NSNumber numberWithInt:[stringOrder indexOfObject:obj1.itemID]] compare:[NSNumber numberWithInt:[stringOrder indexOfObject:obj2.itemID]]]
}];

otherwise you can use the following snippet:

NSArray* sortedKeys = [dict keysSortedByValueUsingComparator:^(id obj1, id obj2)
 {
    return [obj1 compareTo:obj2];
 }

Enjoy the programming!

+1
source

More articles:


All Articles