object c NSArray 数组的排序

1.sortedArrayUsingSelector

（按Key值大小对NSDictionary排序）

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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.       
9. 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

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1. .h  
2. @interface NSDictionary (compare)  
3. {}  
4.   
5. -(NSComparisonResult)compare:(NSDictionary *)otherDictionary;  
6.   
7. @end  
8.   
9. .m  
10. @implementation NSDictionary (compare)  
11.   
12. - (NSComparisonResult)compare: (NSDictionary *)otherDictionary  
13. {  
14.     NSDictionary *tempDictionary = (NSDictionary *)self;  
15.       
16.     NSNumber *number1 = [[tempDictionary allKeys] objectAtIndex:0];  
17.     NSNumber *number2 = [[otherDictionary allKeys] objectAtIndex:0];  
18.       
19.     NSComparisonResult result = [number1 compare:number2];  
20.       
21.     return result == NSOrderedDescending; // 升序  
22. //    return result == NSOrderedAscending;  // 降序  
23. }  
24.   
25. @end  

2.sortedArrayUsingComparator

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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.   
9.   NSArray *resultArray = [array sortedArrayUsingSelector:@selector(compare:)];  
10.   
11. NSArray *resultArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {  
12.       
13.     NSNumber *number1 = [[obj1 allKeys] objectAtIndex:0];  
14.     NSNumber *number2 = [[obj2 allKeys] objectAtIndex:0];  
15.       
16.     NSComparisonResult result = [number1 compare:number2];  
17.       
18.     return result == NSOrderedDescending; // 升序  
19.       return result == NSOrderedAscending;  // 降序  
20. }];  

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

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1. .h  
2. @interface Person : NSObject  
3. {  
4.     NSString  *_name;  
5.       
6.     NSInteger  _age;  
7. }  
8. @property (nonatomic, retain) NSString  *name;  
9. @property (nonatomic, assign) NSInteger  age;  
10. @end  
11.   
12. .m  
13. @implementation Person  
14. @synthesize name = _name;  
15. @synthesize age  = _age;  
16.   
17.   
18. - (void)dealloc  
19. {  
20.     [_name release];  
21.       
22.     [super dealloc];  
23. }  
24.   
25. @end  

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1.     Person *person1 = [[Person alloc] init];  
2.     [person1 setName:@"ABC"];  
3.     [person1 setAge:24];  
4.       
5.     Person *person2 = [[Person alloc] init];  
6.     [person2 setName:@"ACB"];  
7.     [person2 setAge:22];  
8.       
9.     Person *person3 = [[Person alloc] init];  
10.     [person3 setName:@"ABD"];  
11.     [person3 setAge:33];  
12.       
13.     NSMutableArray *array = [NSMutableArray arrayWithObjects:person1, person2, person3, nil];  
14.     [person1 release];  
15.     [person2 release];  
16.     [person3 release];  
17.       
18.     NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"_age" ascending:YES];  
19.       
20.     NSArray *tempArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];  
21.       
22.     for(NSInteger i = 0; i < [tempArray count]; i++)  
23.     {  
24.         NSLog(@"%@--------%d\n", [[tempArray objectAtIndex:i] name], [[tempArray objectAtIndex:i] age]);  
25.     }  
26.       
27. //    [array sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];  
28. //      
29. //    for(NSInteger i = 0; i < [array count]; i++)  
30. //    {  
31. //        NSLog(@"%@--------%d\n", [[array objectAtIndex:i] name], [[array objectAtIndex:i] age]);  
32. //    }  

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

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1.     Person *person1 = [[Person alloc] init];  
2.     [person1 setName:@"ABCD"];  
3.     [person1 setAge:24];  
4.       
5.     Person *person2 = [[Person alloc] init];  
6.     [person2 setName:@"ACBD"];  
7.     [person2 setAge:22];  
8.       
9.     Person *person3 = [[Person alloc] init];  
10.     [person3 setName:@"ABDC"];  
11.     [person3 setAge:33];  
12.       
13.     Person *person4 = [[Person alloc] init];  
14.     [person4 setName:@"ACDB"];  
15.     [person4 setAge:22];  
16.       
17.     NSMutableArray *array = [NSMutableArray arrayWithObjects:person1, person3, person4, person2, nil];  
18.     [person1 release];  
19.     [person2 release];  
20.     [person3 release];  
21.     [person4 release];  
22.       
23.     NSSortDescriptor *sortDescriptor1 = [NSSortDescriptor sortDescriptorWithKey:@"_age" ascending:YES];  
24.     NSSortDescriptor *sortDescriptor2 = [NSSortDescriptor sortDescriptorWithKey:@"_name" ascending:YES];  
25.       
26.     NSArray *tempArray = [array sortedArrayUsingDescriptors:[NSArray arrayWithObjects:sortDescriptor1, sortDescriptor2, nil]];  
27.       
28.     for(NSInteger i = 0; i < [tempArray count]; i++)  
29.     {  
30.         NSLog(@"%@--------%d\n", [[tempArray objectAtIndex:i] name], [[tempArray objectAtIndex:i] age]);  
31.     }  
32.       
33. //    [array sortUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]];  
34. //      
35. //    for(NSInteger i = 0; i < [array count]; i++)  
36. //    {  
37. //        NSLog(@"%@--------%d\n", [[array objectAtIndex:i] name], [[array objectAtIndex:i] age]);  
38. //    }