objective c example

sort.m

#import <Foundation/Foundation.h>

@interface Person : NSObject

@property NSString *firstName;
@property NSString *lastName;
@property NSNumber *age;

@end


@implementation Person

- (NSString *)description {
    return [NSString stringWithFormat:@"%@ %@", self.lastName, self.firstName];
}

@end

int main(int argc, const char *argv[]) {
    @autoreleasepool {
        NSArray *firstNames = @[@"Alice", @"Bob", @"Charlie", @"Quentin"];
        NSArray *lastNames = @[@"Smith", @"Jones", @"Smith", @"Alberts"];
        NSArray *ages = @[@24, @27, @33, @31];
        NSMutableArray *people = [NSMutableArray array];

        [firstNames enumerateObjectsUsingBlock:^(id obj, NSUInteger index, BOOL *stop) {
            Person *person = [[Person alloc] init];
            person.firstName = [firstNames objectAtIndex:index];
            person.lastName = [lastNames objectAtIndex:index];
            person.age = [ages objectAtIndex:index];
            [people addObject:person];
        }];

        NSSortDescriptor *firstNameSortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"firstName"
                                                                                  ascending:YES
                                                                                   selector:@selector(localizedStandardCompare:)];

        NSSortDescriptor *lastNameSortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"lastName"
                                                                                 ascending:YES
                                                                                  selector:@selector(localizedStandardCompare:)];
        NSSortDescriptor *ageSortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"age"
                                                                            ascending:NO];

        NSLog(@"By age: %@", [people sortedArrayUsingDescriptors:@[ageSortDescriptor]]);
        NSLog(@"By first name: %@", [people sortedArrayUsingDescriptors:@[firstNameSortDescriptor]]);
        NSLog(@"By last name, first name: %@", [people sortedArrayUsingDescriptors:@[lastNameSortDescriptor, firstNameSortDescriptor]]);

    }
    return 0;
}