Objective-C语法之NSSortDescriptor

main.m

 #import <Foundation/Foundation.h>
 #import "Person.h"
 /**
  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
  */
 void testSortDescriptor() {
     NSMutableArray *mArrPerson = [[NSMutableArray alloc] initWithCapacity:];
     Person *p = [[Person alloc] initWithName:@"KK" age:];
     [mArrPerson addObject:p];
     p = [[Person alloc] initWithName:@"Candy" age:];
     [mArrPerson addObject:p];
     p = [[Person alloc] initWithName:@"Wiky" age:];
     [mArrPerson addObject:p];
     p = [[Person alloc] initWithName:@"Stone" age:];
     [mArrPerson addObject:p];
     p = [[Person alloc] initWithName:@"Tom" age:];
     [mArrPerson addObject:p];
     p = [[Person alloc] initWithName:@"Sherlock" age:];
     [mArrPerson addObject:p];
     p = [[Person alloc] initWithName:@"Alex" age:];
     [mArrPerson addObject:p];
     p = [[Person alloc] initWithName:@"Keye" age:];
     [mArrPerson addObject:p];

     NSLog(@"按Person的age属性（降序）和name属性（升序）");
     NSSortDescriptor *sortByAge = [[NSSortDescriptor alloc] initWithKey:@"age" ascending:NO];
     NSSortDescriptor *sortByName = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
     [mArrPerson sortUsingDescriptors:@[sortByAge, sortByName]];
     for (Person *p in mArrPerson) {
         NSLog(@"age=%ld, name=%@", p.age, p.name);
     }
 }
 int main(int argc, const char * argv[]) {
     @autoreleasepool {
         testSortDescriptor();
     }
     return ;
 }

Person.h

 #import <Foundation/Foundation.h>
 @interface Person : NSObject
 @property (nonatomic, strong) NSString *name;
 @property (nonatomic, assign) NSInteger age;

 - (id)initWithName:(NSString *)name age:(NSInteger)age;
 @end

Person.m

 #import "Person.h"

 @implementation Person
 - (id)initWithName:(NSString *)name age:(NSInteger)age {
     if (self = [super init]) {
         _name = name;
         _age = age;
     }
     return self;
 }
 @end

结果：

 -- ::13.240 OCNSSortDescriptor[:] 按Person的age属性（降序）和name属性（升序）
 -- ::13.241 OCNSSortDescriptor[:] age=, name=Stone
 -- ::13.241 OCNSSortDescriptor[:] age=, name=Alex
 -- ::13.241 OCNSSortDescriptor[:] age=, name=Keye
 -- ::13.241 OCNSSortDescriptor[:] age=, name=Tom
 -- ::13.242 OCNSSortDescriptor[:] age=, name=Sherlock
 -- ::13.242 OCNSSortDescriptor[:] age=, name=Wiky
 -- ::13.242 OCNSSortDescriptor[:] age=, name=KK
 -- ::13.242 OCNSSortDescriptor[:] age=, name=Candy