Sort NSMutableArray based on strings from another NSArray - objective-c

I have an NSArray of strings that I want to use as my sort order:
NSArray *permissionTypes = [NSArray arrayWithObjects:#"Read", #"Write", #"Admin", nil];
I then have a NSMutableArray that may or may not have all three of those permissions types, but sometimes it will only be 2, sometimes 1, but I still want it sorted based on my permissionsTypes array.
NSMutableArray *order = [NSMutableArray arrayWithArray:[permissions allKeys]];
How can I always sort my order array correctly based on my using the permissionTypes array as a key?

I would go about this by creating a struct or an object to hold the permission types.
Then you can have...
PermissionType
--------------
Name: Read
Order: 1
PermissionType
--------------
Name: Write
Order: 2
and so on.
Then you only need the actual array of these objects and you can sort by the order value.
[array sortUsingComparator:^NSComparisonResult(PermissionType *obj1, PermissionType *obj2) {
return [obj1.order compare:obj2.order];
}];
This will order the array by the order field.

NSMutableArray *sortDescriptors = [NSMutableArray array];
for (NSString *type in permissionTypes) {
NSSortDescriptor *descriptor = [[[NSSortDescriptor alloc] initWithKey:type ascending:YES] autorelease];
[sortDescriptors addObject:descriptor];
}
sortedArray = [myArray sortedArrayUsingDescriptors:sortDescriptors];

Use whichever sorting method on NSMutableArray you prefer, you will either provide a block or a selector to use for comparing two elements. In that block/selector rather than comparing the two strings passed in directly look each up in your permissionTypes array using indexOfObject: and compare the resulting index values returned.

I suggest you another approuch:
- (void)viewDidLoad
{
[super viewDidLoad];
arrayPermissions = [[NSMutableArray alloc] init];
NSDictionary *dicRead = [NSDictionary dictionaryWithObjectsAndKeys:
#"Read", #"Permission", nil];
NSDictionary *dicWrite = [NSDictionary dictionaryWithObjectsAndKeys:
#"Write", #"Permission", nil];
NSDictionary *dicAdmin = [NSDictionary dictionaryWithObjectsAndKeys:
#"Admin", #"Permission", nil];
NSLog(#"my dicRead = %#", dicRead);
NSLog(#"my dicWrite = %#", dicWrite);
NSLog(#"my dicAdmin = %#", dicAdmin);
[arrayPermissions addObject:dicRead];
[arrayPermissions addObject:dicWrite];
[arrayPermissions addObject:dicAdmin];
NSLog(#"arrayPermissions is: %#", arrayPermissions);
// create a temporary Dict again
NSDictionary *temp =[[NSDictionary alloc]
initWithObjectsAndKeys: arrayPermissions, #"Permission", nil];
// declare one dictionary in header class for global use and called "filteredDict"
self.filteredDict = temp;
self.sortedKeys =[[self.filteredDict allKeys]
sortedArrayUsingSelector:#selector(compare:)];
NSLog(#"sortedKeys is: %i", sortedKeys.count);
NSLog(#"sortedKeys is: %#", sortedKeys);
}
hope help

Related

Sorting JSON Data by date

Hi I'm getting data online from a JSON file and I'm trying to sort it by date in descending order, I've done it before using an XML parser using an RSS feed and tried to use the same concept but can't seem to get it and it crashes every time.
NSData *data = [NSData dataWithContentsOfURL:url];
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
NSDictionary *dataDict = [dict objectForKey:#"data"];
NSArray *array = [dataDict objectForKey:#"items"];
for (int i=0; i<[array count]; i++) {
SongInfo *song = [[SongInfo alloc]init];
NSMutableDictionary *entry = [array objectAtIndex:i];
song.uploaded = [entry objectForKey:#"uploaded"];
song.uploader = [entry objectForKey:#"uploader"];
NSComparator comparator = ^(NSDictionary *a, NSDictionary *b) {
return [a[#"uploaded"] compare:b[#"uploaded"]];
};
NSUInteger index = [songsArray indexOfObject:entry
inSortedRange:NSMakeRange(0, [songsArray count])
options:NSBinarySearchingInsertionIndex
usingComparator:comparator];
[songsArray insertObject:song atIndex:index];
EDIT: Managed to fix it by using the NSSortDescriptor and putting it into an array and then back into the same array, not sure if there is a better way to do this but this is how I did it...
NSSortDescriptor *sortDescriptor;
sortDescriptor = [[NSSortDescriptor alloc] initWithKey:#"uploaded"
ascending:NO];
NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
NSArray *sortedArray;
sortedArray = [songsArray sortedArrayUsingDescriptors:sortDescriptors];
songsArray = [NSMutableArray arrayWithArray:sortedArray];
// [songsArray addObject:[song copy] atIndex:index];
[songsArray addObject:song];
You're comparing objects inserted in the songsArray with a comparator that takes in two dictionaries. It seems like the comparator should compare SongInfo objects rather than NSDictionaries.
We can't see what songsArray is. Creating a sorted array manually like you do is really inefficient. Call the NSArray method sortedArrayUsingComparator instead, and there is no need to create SongInfo objects.
On the other hand, if an array of SongInfo* is what you want, create that array first as an NSMutableArray with all the SongInfo's from the JSON data, then sort that array by calling sortUsingComparator.
Note that in the comparator block you can actually use the type of the object: So in the first case NSDictionary* instead of id, in the second case SongInfo* instead of id.

Sorting NSMutableArray by date

I want to sort a mutable array by date. My array contains several dict with keys say:key1,key2,birthday.Now, I have to sort by its birthday key:
I know that this can be done using:
NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:#"birthday" ascending:YES];
[myArray sortUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];
But my problem is that I want to sort only those arrays, which don’t contain empty birthday field. My array will contains several empty birthday fields. I don’t want to sort those.
Finally I have to load these in table view through [self.mTable reloadData];.
First collect the indices of all objetcs without a birthday.
NSIndexSet *indexSet = [NSIndexSet indexSet];
[array enumerateObjectsUsingBlock:^(NSDictionary *dict, NSUInteger idx, BOOL *stop)
{
if(![[dict allKeys] containsObject:#"birthday"]){
[indexSet addIndex:idx];
}
}];
Now remove them from the original array
[array removeObjectsAtIndexes:indexSet];
Using a comparator block, sorting could look like
[array sortUsingComparator: ^(NSDictionary *d1, NSDictionary *d2) {
NSDate *date1 = [d1 objectForKey:#"birthday"];
NSDate *date2 = [d2 objectForKey:#"birthday"];
return [date1 compare:date2]
}
Create a different array to back your table view like this:
NSDictionary* obj1 = [NSDictionary dictionaryWithObject: [NSDate date] forKey: #"birthday"];
NSDictionary* obj2 = [NSDictionary dictionaryWithObject: [NSDate dateWithTimeIntervalSince1970: 0] forKey: #"birthday"];
NSDictionary* obj3 = [NSDictionary dictionaryWithObject: #"wow" forKey: #"no_birthday"];
NSArray* all = [NSArray arrayWithObjects: obj1, obj2, obj3, nil];
NSArray* onlyWithBirthday = [all valueForKeyPath: #"#unionOfObjects.birthday"];
And if you need the full objects for the table view, continue with this code:
NSPredicate* filter = [NSPredicate predicateWithFormat: #"SELF.birthday IN %#", onlyWithBirthday];
NSArray* datasource = [all filteredArrayUsingPredicate: filter];
Then you can apply your sort method of choice.

How can I retrieve all the contents of an NSDictionary?

I want to select and retrieve all the contents from an NSDictionary. I have a structure like this
- (void)viewDidLoad {
[super viewDidLoad];
listaOggetti = [[NSMutableArray alloc] init];
NSArray *arrayOne = [NSArray arrayWithObjects: #"First",#"Second",#"Third", nil];
NSArray *sortedOne = [arrayOne sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)];
NSDictionary *dictOne = [NSDictionary dictionaryWithObject:sortedOne forKey:#"Elementi"];
NSArray *arrayTWo = [NSArray arrayWithObjects:#"First1",#"Second1" ..., nil];
NSArray *sortedTwo = [arrayTwo sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)];
NSDictionary *dictTwo = [NSDictionary dictionaryWithObject:sortedTWo forKey:#"Elementi"];
NSArray *arrayThree = [NSArray arrayWithObjects:#"First2",#"Second2" ... , nil];
NSArray *sortedThree = [arrayThree sortedArrayUsingSelector:#selector(localizedCaseInsensitiveCompare:)];
NSDictionary *dictThree = [NSDictionary dictionaryWithObject:sortedThree forKey:#"Elementi"];
[listaOggetti addObject:dictOne];
[listaOggetti addObject:dictTwo];
[listaOggetti addObject:dictThree];
}
And I want to retrieve all the objects for the key #"Elementi" (should be around 45) in order to add them in another array, like:
NSDictionary *dict = [listaOggetti objectAtIndex:indexPath.section];
NSArray *array = [dict objectForKey:#"Elementi"];
cellValue = [array objectAtIndex:indexPath.row] ;
(With this, dict is only 9 objects filled in my project).
At the end, the *array should be around 45 objects filled. I tried with allValues, but didn't work.
How can I fix it?
The easiest is to do this in -viewDidLoad:
NSMutableArray *allObjects = [[NSMutableArray alloc] init];
[allObjects addObjectsFromArray:sortedOne];
[allObjects addObjectsFromArray:sortedTwo];
[allObjects addObjectsFromArray:sortedThree];
Alternately, you can get them from the dictionaries in a similar fashion:
NSMutableArray *allObjects = [[NSMutableArray alloc] init];
[allObjects addObjectsFromArray:[[listaOggetti objectAtIndex:0] objectForKey#"Elementi"];
[allObjects addObjectsFromArray:[[listaOggetti objectAtIndex:1] objectForKey#"Elementi"];
[allObjects addObjectsFromArray:[[listaOggetti objectAtIndex:2] objectForKey#"Elementi"];
What you are failing to understand is that listaOggetti is an NSMutableArray containing three objects. When you call
NSDictionary *dict = [listaOggetti objectAtIndex:indexPath.section];
the result is that dict is a single dictionary, one of the three objects in listaOggetti. Therefore when you call
NSArray *array = [dict objectForKey:#"Elementi"];
the result is that array is the object for the key #"Elementi" of that one single dictionary dict. Your code makes no attempt to combine the three DIFFERENT dictionaries or to combine the three arrays, each set as objectForKey:#"Elementi" for the three DIFFERENT dictionaries.
If you want one array that is the concatenation of all three different arrays, then use one of the snippets provided above. In both of these snippets, the result is that allObjects is an NSMutableArray containing all three arrays, in order.

Sort an NSArray with NSDictionary

I'm using NSSortDiscriptors to sort an NSArray.
Every index in the array contains a dictionary with key,value entries. This dictionary also holds another dictionary.
My problem that I want solve is to sort the array based on values on the first dictionary, but also on some values in the dictionary it contains.
The following is the sort method I use for the other values in the array.
- (void)sortArray {
if ([array count] != 0) {
// Reports sortingDescriptors
NSSortDescriptor * city = [[NSSortDescriptor alloc] initWithKey:#"City" ascending:YES];
NSSortDescriptor * name = [[NSSortDescriptor alloc] initWithKey:#"Name" ascending:YES];
NSSortDescriptor * country = [[NSSortDescriptor alloc] initWithKey:#"Country" ascending:YES];
[reportsArray sortUsingDescriptors:[NSArray arrayWithObjects:city, name, country, nil]];
[name release];
[city release];
[country release];
}
}
The array looks like this:
[{name = "";
city = "";
country = "";
date = {
dateAdded = "";
dateRemoved = "";
}
}];
So I also want to sort on, if have value on dateAdded for example.
You can specify a key path when you create the NSSortDescriptor, this way you can sort the NSArray with a NSDictionary.
You might want to check if the dictionary contains a value like that :
// you can't set nil as a value for a key
if([yourDictionary objectForKey:#"yourKey"] == [NSNull null]) { ... }
Then you need to sort remaining objects but the dictionary, to do so, make a copy of your array without the dictionary entry by doing something like :
NSMutableArray *tmpArray = [NSMutableArray arrayWithArray:firstArray];
[tmpArray removeObjectAtIndex:theIndexOfTheDictionary];
// sort your array, don't forget to catch the returned value
NSMutableArray *sortedArray = [tmpArray sortUsingDescriptors:[NSArray arrayWithObjects:city, name, country, nil]];
// finally, put the dictionary back in (if needed)
[sortedArray insertObject:theDictionary atIndex:theIndexYouWant];
Are you saying that the objects in the array have a City, Name and Country property but also a dictionary property and you want to sort on one of the keys in the dictionary? Or are you saying that the entries in the array are dictionaries but sometimes the City, Name or Country key is missing? Or are you saying that some of the entries are dictionaries and some are objects with the listed properties?
In any case, you can get more flexibility by creating a sort descriptor using initWithKey:ascending:comparator:. This allows you to supply a comparator block as the sort function which is more flexible than a straight selector e.g.
NSComparator mySort = ^(id obj1, id obj2)
{
NSComparisonResult ret = NSOrderedSame;
if ([obj1 isKindOfClass: [NSDictionary class]] && ![obj2 isKindOfClass: NSDictionary class]])
{
ret = NSOrderedAscending;
}
else if (![obj1 isKindOfClass: [NSDictionary class]] && [obj2 isKindOfClass: NSDictionary class]])
{
ret = NSOrderedDescending;
}
return ret;
};
NSSortDescriptor* descriptor = [[NSSortDescriptor alloc] initWithKey: #"self" ascending: YES comparator: mySort];
will give you a sort descriptor that sorts the array putting all the NSDictionaries first and other objects afterwards. (self is a key possessed by all NSObjects that returns the object itself).
NSArray *unsortedArray=[NSArray arrayWithObjects:[NSDictionary dictionaryWithObjectsAndKeys:#"anil",#"personInDictionary.lastName" ,nil],[NSDictionary dictionaryWithObjectsAndKeys:#"aneelu",#"personInDictionary.lastName", nil] ,[NSDictionary dictionaryWithObjectsAndKeys:#"kumar",#"anil.lastName", nil] ,nil];
NSSortDescriptor * descriptor = [[[NSSortDescriptor alloc] initWithKey:#"personInDictionary.lastName" ascending:YES] autorelease]; // 1
NSArray * sortedArray = [unsortedArray sortedArrayUsingDescriptors:
[NSArray arrayWithObject:descriptor]];
NSLog(#"sortedArray values %#",sortedArray);
for (id object in [sortedArray valueForKey:#"personInDictionary.lastName"]) {
NSLog(#"sortedArray value %#",object);
}

Objective-C - How to compare arrays and extract the difference?

Possible duplicate: comparing-two-arrays
I have two NSArray and I'd like to create a new Array with objects from the second array but not
included in the first array.
Example:
NSMutableArray *firstArray = [NSMutableArray arrayWithObjects:#"Bill", #"Ben", #"Chris", #"Melissa", nil];
NSMutableArray *secondArray = [NSMutableArray arrayWithObjects:#"Bill", #"Paul", nil];
The resulting array should be:
[#"Paul", nil];
I solved this problem with a double loop comparing objects into the inner one.
Is there a better solutions ?
[secondArray removeObjectsInArray:firstArray];
This idea was taken from another answer.
If duplicate items are not significant in the arrays, you can use the minusSet: operation of NSMutableSet:
NSMutableArray *firstArray = [NSMutableArray arrayWithObjects:#"Bill", #"Ben", #"Chris", #"Melissa", nil];
NSMutableArray *secondArray = [NSMutableArray arrayWithObjects:#"Bill", #"Paul", nil];
NSSet *firstSet = [NSSet setWithArray:firstArray];
NSMutableSet *secondSet = [NSMutableSet setWithCapacity:[secondArray count]];
[secondSet addObjectsFromArray:secondArray];
[secondSet minusSet:firstSet]; // result is in `secondSet`
I want to compare images from two NSArray.
One Array, I was getting from Core Database. Second I have constant array objects.
I want to know that object of second array is present in Core database or not.
Here is code which i used.
// All object from core data and take into array.
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]initWithEntityName:#"student"];
NSArray *dbresult = [[NSArray alloc]init];
NSError *error;
#try {
dbresult = [context executeFetchRequest:fetchRequest error:&error];
}
#catch (NSException *exception) {
NSString *logerror = [NSString stringWithFormat:#"error in fetching Rooms from coredata = %#",exception.description];
NSLog(logerror)
}
#finally {
}
/*
Get Unused images from list
*/
NSMutableArray *usedImages = [dbresult valueForKey:#"roomImageLocalPath"];
NSMutableSet *fSet = [NSMutableSet setWithArray:usedImages];
NSMutableSet *sSet = [NSMutableSet setWithCapacity:[newImages count]];
[sSet addObjectsFromArray:newImages];
[sSet minusSet:fSet];
NSArray *unusedImages = [secondSet allObjects];
NSLog(#"unusedImages %#",unusedImages);