[objective-c] How to sort a NSArray alphabetically?

How can I sort an array filled with [UIFont familyNames] into alphabetical order?

This question is related to objective-c sorting

The answer is


The simplest approach is, to provide a sort selector (Apple's documentation for details)

Objective-C

sortedArray = [anArray sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];

Swift

let descriptor: NSSortDescriptor = NSSortDescriptor(key: "YourKey", ascending: true, selector: "localizedCaseInsensitiveCompare:")
let sortedResults: NSArray = temparray.sortedArrayUsingDescriptors([descriptor])

Apple provides several selectors for alphabetic sorting:

  • compare:
  • caseInsensitiveCompare:
  • localizedCompare:
  • localizedCaseInsensitiveCompare:
  • localizedStandardCompare:

Swift

var students = ["Kofi", "Abena", "Peter", "Kweku", "Akosua"]
students.sort()
print(students)
// Prints "["Abena", "Akosua", "Kofi", "Kweku", "Peter"]"

Reference


A more powerful way of sorting a list of NSString to use things like NSNumericSearch :

NSArray *sortedArrayOfString = [arrayOfString sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
            return [(NSString *)obj1 compare:(NSString *)obj2 options:NSNumericSearch];
        }];

Combined with SortDescriptor, that would give something like :

NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES comparator:^NSComparisonResult(id obj1, id obj2) {
        return [(NSString *)obj1 compare:(NSString *)obj2 options:NSNumericSearch];
    }];
NSArray *sortedArray = [anArray sortedArrayUsingDescriptors:[NSArray arrayWithObject:sort]];

Another easy method to sort an array of strings consists by using the NSString description property this way:

NSSortDescriptor *valueDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"description" ascending:YES];
arrayOfSortedStrings = [arrayOfNotSortedStrings sortedArrayUsingDescriptors:@[valueDescriptor]];

-(IBAction)SegmentbtnCLK:(id)sender
{ [self sortArryofDictionary];
    [self.objtable reloadData];}
-(void)sortArryofDictionary
{ NSSortDescriptor *sorter;
    switch (sortcontrol.selectedSegmentIndex)
    {case 0:
            sorter=[[NSSortDescriptor alloc]initWithKey:@"Name" ascending:YES];
            break;
        case 1:
            sorter=[[NSSortDescriptor alloc]initWithKey:@"Age" ascending:YES];
            default:
            break; }
    NSArray *sortdiscriptor=[[NSArray alloc]initWithObjects:sorter, nil];
    [arr sortUsingDescriptors:sortdiscriptor];
    }

This already has good answers for most purposes, but I'll add mine which is more specific.

In English, normally when we alphabetise, we ignore the word "the" at the beginning of a phrase. So "The United States" would be ordered under "U" and not "T".

This does that for you.

It would probably be best to put these in categories.

// Sort an array of NSStrings alphabetically, ignoring the word "the" at the beginning of a string.

-(NSArray*) sortArrayAlphabeticallyIgnoringThes:(NSArray*) unsortedArray {

    NSArray * sortedArray = [unsortedArray sortedArrayUsingComparator:^NSComparisonResult(NSString* a, NSString* b) {

        //find the strings that will actually be compared for alphabetical ordering
        NSString* firstStringToCompare = [self stringByRemovingPrecedingThe:a];
        NSString* secondStringToCompare = [self stringByRemovingPrecedingThe:b];

        return [firstStringToCompare compare:secondStringToCompare];
    }];
    return sortedArray;
}

// Remove "the"s, also removes preceding white spaces that are left as a result. Assumes no preceding whitespaces to start with. nb: Trailing white spaces will be deleted too.

-(NSString*) stringByRemovingPrecedingThe:(NSString*) originalString {
    NSString* result;
    if ([[originalString substringToIndex:3].lowercaseString isEqualToString:@"the"]) {
        result = [[originalString substringFromIndex:3] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    }
    else {
        result = originalString;
    }
    return result;
}

The other answers provided here mention using @selector(localizedCaseInsensitiveCompare:) This works great for an array of NSString, however if you want to extend this to another type of object, and sort those objects according to a 'name' property, you should do this instead:

NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES];
sortedArray=[anArray sortedArrayUsingDescriptors:@[sort]];

Your objects will be sorted according to the name property of those objects.

If you want the sorting to be case insensitive, you would need to set the descriptor like this

NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES selector:@selector(caseInsensitiveCompare:)];

Use below code for sorting in alphabetical order:

    NSArray *unsortedStrings = @[@"Verdana", @"MS San Serif", @"Times New Roman",@"Chalkduster",@"Impact"];

    NSArray *sortedStrings =
    [unsortedStrings sortedArrayUsingSelector:@selector(compare:)];

    NSLog(@"Unsorted Array : %@",unsortedStrings);        
    NSLog(@"Sorted Array : %@",sortedStrings);

Below is console log :

2015-04-02 16:17:50.614 ToDoList[2133:100512] Unsorted Array : (
    Verdana,
    "MS San Serif",
    "Times New Roman",
    Chalkduster,
    Impact
)

2015-04-02 16:17:50.615 ToDoList[2133:100512] Sorted Array : (
    Chalkduster,
    Impact,
    "MS San Serif",
    "Times New Roman",
    Verdana
)