NSArray的排序方法

转自：http://blog.csdn.net/lixuwen521/article/details/7848893

1.sortedArrayUsingSelector

（按Key值大小对NSDictionary排序）

1. NSMutableArray *array = [NSMutableArray arrayWithObjects:
2. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj0", [NSNumber numberWithInt:0], nil],
3. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj5", [NSNumber numberWithInt:5], nil],
4. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj2", [NSNumber numberWithInt:2], nil],
5. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj3", [NSNumber numberWithInt:3], nil],
6. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj1", [NSNumber numberWithInt:1], nil],
7. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj4", [NSNumber numberWithInt:4], nil], nil];
8. NSArray *resultArray = [array sortedArrayUsingSelector:@selector(compare:)];

因为NSDictionary没有compare的排序比较方法，所以需要我们自己写

1. .h
2. @interface NSDictionary (compare)
3. {}
4. -(NSComparisonResult)compare:(NSDictionary *)otherDictionary;
5. @end
6. .m
7. @implementation NSDictionary (compare)
8. - (NSComparisonResult)compare: (NSDictionary *)otherDictionary
9. {
10. NSDictionary *tempDictionary = (NSDictionary *)self;
11. NSNumber *number1 = [[tempDictionary allKeys] objectAtIndex:0];
12. NSNumber *number2 = [[otherDictionary allKeys] objectAtIndex:0];
13. NSComparisonResult result = [number1 compare:number2];
14. return result == NSOrderedDescending; // 升序
15. //    return result == NSOrderedAscending;  // 降序
16. }
17. @end

2.sortedArrayUsingComparator

1. NSMutableArray *array = [NSMutableArray arrayWithObjects:
2. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj0", [NSNumber numberWithInt:0], nil],
3. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj5", [NSNumber numberWithInt:5], nil],
4. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj2", [NSNumber numberWithInt:2], nil],
5. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj3", [NSNumber numberWithInt:3], nil],
6. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj1", [NSNumber numberWithInt:1], nil],
7. [NSDictionary dictionaryWithObjectsAndKeys:@"Obj4", [NSNumber numberWithInt:4], nil], nil];
8. NSArray *resultArray = [array sortedArrayUsingSelector:@selector(compare:)];
9. NSArray *resultArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
10. NSNumber *number1 = [[obj1 allKeys] objectAtIndex:0];
11. NSNumber *number2 = [[obj2 allKeys] objectAtIndex:0];
12. NSComparisonResult result = [number1 compare:number2];
13. return result == NSOrderedDescending; // 升序
14. return result == NSOrderedAscending;  // 降序
15. }];

3.sortedArrayUsingDescriptors & sortUsingDescriptors

前者带返回值，是NSArray的方法，排好序的数组是返回值中的数组；

后者不带返回值，是NSMutableArray的方法，是对当前数组自己排序

1. .h
2. @interface Person : NSObject
3. {
4. NSString  *_name;
5. NSInteger  _age;
6. }
7. @property (nonatomic, retain) NSString  *name;
8. @property (nonatomic, assign) NSInteger  age;
9. @end
10. .m
11. @implementation Person
12. @synthesize name = _name;
13. @synthesize age  = _age;
14. - (void)dealloc
15. {
16. [_name release];
17. [super dealloc];
18. }
19. @end

1. Person *person1 = [[Person alloc] init];
2. [person1 setName:@"ABC"];
3. [person1 setAge:24];
4. Person *person2 = [[Person alloc] init];
5. [person2 setName:@"ACB"];
6. [person2 setAge:22];
7. Person *person3 = [[Person alloc] init];
8. [person3 setName:@"ABD"];
9. [person3 setAge:33];
10. NSMutableArray *array = [NSMutableArray arrayWithObjects:person1, person2, person3, nil];
11. [person1 release];
12. [person2 release];
13. [person3 release];
14. NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"_age" ascending:YES];
15. NSArray *tempArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
16. for(NSInteger i = 0; i < [tempArray count]; i++)
17. {
18. NSLog(@"%@--------%d\n", [[tempArray objectAtIndex:i] name], [[tempArray objectAtIndex:i] age]);
19. }
20. //    [array sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
21. //
22. //    for(NSInteger i = 0; i < [array count]; i++)
23. //    {
24. //        NSLog(@"%@--------%d\n", [[array objectAtIndex:i] name], [[array objectAtIndex:i] age]);
25. //    }

sortDescriptorWithKey:@"_age",以age作为标准来做比较。

1. Person *person1 = [[Person alloc] init];
2. [person1 setName:@"ABCD"];
3. [person1 setAge:24];
4. Person *person2 = [[Person alloc] init];
5. [person2 setName:@"ACBD"];
6. [person2 setAge:22];
7. Person *person3 = [[Person alloc] init];
8. [person3 setName:@"ABDC"];
9. [person3 setAge:33];
10. Person *person4 = [[Person alloc] init];
11. [person4 setName:@"ACDB"];
12. [person4 setAge:22];
13. NSMutableArray *array = [NSMutableArray arrayWithObjects:person1, person3, person4, person2, nil];
14. [person1 release];
15. [person2 release];
16. [person3 release];
17. [person4 release];
18. NSSortDescriptor *sortDescriptor1 = [NSSortDescriptor sortDescriptorWithKey:@"_age" ascending:YES];
19. NSSortDescriptor *sortDescriptor2 = [NSSortDescriptor sortDescriptorWithKey:@"_name" ascending:YES];
20. NSArray *tempArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObjects:sortDescriptor1, sortDescriptor2, nil]];
21. for(NSInteger i = 0; i < [tempArray count]; i++)
22. {
23. NSLog(@"%@--------%d\n", [[tempArray objectAtIndex:i] name], [[tempArray objectAtIndex:i] age]);
24. }
25. //    [array sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];
26. //
27. //    for(NSInteger i = 0; i < [array count]; i++)
28. //    {
29. //        NSLog(@"%@--------%d\n", [[array objectAtIndex:i] name], [[array objectAtIndex:i] age]);
30. //    }

NSSortDescriptor *sortDescriptor1 = [NSSortDescriptorsortDescriptorWithKey:@"_age"ascending:YES];

NSSortDescriptor *sortDescriptor2 = [NSSortDescriptorsortDescriptorWithKey:@"_name"ascending:YES];

NSArray *tempArray = [array sortedArrayUsingDescriptors:[NSArrayarrayWithObjects:sortDescriptor1, sortDescriptor2, nil]];

这里的NSArray中的第一元素表示首先按照这个元素的升序或者降序进行排序,对于有重复项的，再按照第二元素进行排序，依次进行类推