Objective-C语法之NSSortDescriptor

 1 #import <Foundation/Foundation.h>
 2 #import "Person.h"
 3 /**
 4  NSSortDescriptor 可以实现按照对象的属性进行排序；支持多个属性排序。比如我们有个Person对象，它有名字（name）和年龄（age）两个属性，我们需要按Person的age属性（降序）和name属性（升序）来输出Person对象数组信息
 5  */
 6 void testSortDescriptor() {
 7     NSMutableArray *mArrPerson = [[NSMutableArray alloc] initWithCapacity:5];
 8     Person *p = [[Person alloc] initWithName:@"KK" age:23];
 9     [mArrPerson addObject:p];
10     p = [[Person alloc] initWithName:@"Candy" age:22];
11     [mArrPerson addObject:p];
12     p = [[Person alloc] initWithName:@"Wiky" age:27];
13     [mArrPerson addObject:p];
14     p = [[Person alloc] initWithName:@"Stone" age:32];
15     [mArrPerson addObject:p];
16     p = [[Person alloc] initWithName:@"Tom" age:28];
17     [mArrPerson addObject:p];
18     p = [[Person alloc] initWithName:@"Sherlock" age:27];
19     [mArrPerson addObject:p];
20     p = [[Person alloc] initWithName:@"Alex" age:29];
21     [mArrPerson addObject:p];
22     p = [[Person alloc] initWithName:@"Keye" age:28];
23     [mArrPerson addObject:p];
24     
25     NSLog(@"按Person的age属性（降序）和name属性（升序）");
26     NSSortDescriptor *sortByAge = [[NSSortDescriptor alloc] initWithKey:@"age" ascending:NO];
27     NSSortDescriptor *sortByName = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
28     [mArrPerson sortUsingDescriptors:@[sortByAge, sortByName]];
29     for (Person *p in mArrPerson) {
30         NSLog(@"age=%ld, name=%@", p.age, p.name);
31     }
32 }
33 int main(int argc, const char * argv[]) {
34     @autoreleasepool {
35         testSortDescriptor();
36     }
37     return 0;
38 }

1 #import <Foundation/Foundation.h>
2 @interface Person : NSObject
3 @property (nonatomic, strong) NSString *name;
4 @property (nonatomic, assign) NSInteger age;
5 
6 - (id)initWithName:(NSString *)name age:(NSInteger)age;
7 @end

 1 #import "Person.h"
 2 
 3 @implementation Person
 4 - (id)initWithName:(NSString *)name age:(NSInteger)age {
 5     if (self = [super init]) {
 6         _name = name;
 7         _age = age;
 8     }
 9     return self;
10 }
11 @end

1 2015-03-28 12:27:13.240 OCNSSortDescriptor[1276:49262] 按Person的age属性（降序）和name属性（升序）
2 2015-03-28 12:27:13.241 OCNSSortDescriptor[1276:49262] age=32, name=Stone
3 2015-03-28 12:27:13.241 OCNSSortDescriptor[1276:49262] age=29, name=Alex
4 2015-03-28 12:27:13.241 OCNSSortDescriptor[1276:49262] age=28, name=Keye
5 2015-03-28 12:27:13.241 OCNSSortDescriptor[1276:49262] age=28, name=Tom
6 2015-03-28 12:27:13.242 OCNSSortDescriptor[1276:49262] age=27, name=Sherlock
7 2015-03-28 12:27:13.242 OCNSSortDescriptor[1276:49262] age=27, name=Wiky
8 2015-03-28 12:27:13.242 OCNSSortDescriptor[1276:49262] age=23, name=KK
9 2015-03-28 12:27:13.242 OCNSSortDescriptor[1276:49262] age=22, name=Candy