大体上,OC中常用的数组排序有以下几种方法:sortedArrayUsingSelector:;sortedArrayUsingComparator:;sortedArrayUsingDescriptors:。
1、简单排序(sortedArrayUsingSelector:) 如果只是对字符串的排序,可以利用sortedArrayUsingSelector:方法就可以了,代码如下
//简单排序
1 void sortArray1(){ 2 3 NSArray *array = [NSArrayarrayWithObjects:@"abc",@"456",@"123",@"789",@"ef", nil]; 4 5 NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(compare:)]; 6 7 NSLog(@"排序后:%@",sortedArray); 8 9 }
当然,除了利用字符串自带的compare:方法,也可以自己写compare:方法,进行对象的比较;如下: 首先是新建了 Person 类,实现方法如下(头文件就省了):
1 #import "Person.h" 2 3 @implementation Person 4 5 6 7 //直接实现静态方法,获取带有name和age的Person对象 8 9 +(Person *)personWithAge:(int) age withName:(NSString *)name{ 10 11 Person *person = [[Person alloc] init]; 12 13 person.age = age; 14 15 person.name = name; 16 17 return person; 18 19 } 20 21 22 23 //自定义排序方法 24 25 -(NSComparisonResult)comparePerson:(Person *)person{ 26 27 //默认按年龄排序 28 29 NSComparisonResult result = [[NSNumber numberWithInt:person.age]compare:[NSNumber numberWithInt:self.age]];//注意:基本数据类型要进行数据转换 30 31 //如果年龄一样,就按照名字排序 32 33 if (result == NSOrderedSame) { 34 35 result = [self.name compare:person.name]; 36 37 } 38 39 return result; 40 41 } 42 43 44 45 46 47 @end
主函数代码如下:
1 void sortArray2(){ 2 3 Person *p1 = [Person personWithAge:23 withName:@"zhangsan"]; 4 5 Person *p2 = [Person personWithAge:21 withName:@"lisi"]; 6 7 Person *p3 = [Person personWithAge:24 withName:@"wangwu"]; 8 9 Person *p4 = [Person personWithAge:24 withName:@"liwu"]; 10 11 Person *p5 = [Person personWithAge:20 withName:@"liwu"]; 12 13 NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil]; 14 15 NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(comparePerson:)]; 16 17 NSLog(@"排序后:%@",sortedArray); 18 19 }
2、利用block语法(sortedArrayUsingComparator:) 苹果官方提供了block语法,比较方便。其中数组排序可以用sortedArrayUsingComparator:方法,代码如下:
1 void sortArray3(){ 2 3 NSArray *array = [NSArrayarrayWithObjects:@"1bc",@"4b6",@"123",@"789",@"3ef", nil]; 4 5 NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) { 6 7 8 9 //这里的代码可以参照上面compare:默认的排序方法,也可以把自定义的方法写在这里,给对象排序 10 11 NSComparisonResult result = [obj1 compare:obj2]; 12 13 return result; 14 15 }]; 16 17 NSLog(@"排序后:%@",sortedArray); 18 19 }
3、高级排序(sortedArrayUsingDescriptors:) 如果是这样一种情况呢?Person类里有另外一个类的变量,比如说Person类除了name,age变量,还有一辆车Car类型,Car类里有个name属性。对Person对象进行排序,有这样的要求:按照Car的name排序,如果是同一辆车,也就是Car的name相同,那么再按照年龄进行排序,如果年龄也相同,最后按照Person的name进行排序。 上面这样就要使用第三种方法,利用排序描述器,不多说,有兴趣可以看看API介绍。代码如下: 首先写个Car类,实现类Car.m代码如下:
#import "Car.h" @implementation Car +(Car *)initWithName:(NSString *)name{ Car *car = [[Car alloc] init]; car.name = name; return car; } @end
然后改写Person类,实现类Person.m代码如下:
1 #import "Person.h" 2 3 #import "Car.h" 4 5 @implementation Person 6 7 8 9 +(Person *)personWithAge:(int)age withName:(NSString *)name withCar:(Car *)car{ 10 11 Person *person = [[Person alloc] init]; 12 13 person.age = age; 14 15 person.name = name; 16 17 person.car = car; 18 19 return person; 20 21 } 22 23 24 25 //这里重写description方法,用于最后测试排序结果显示 26 27 -(NSString *)description{ 28 29 return [NSString stringWithFormat:@"age is %zi , name is %@, car is %@",_age,_name,_car.name]; 30 31 } 32 33 34 @end
主函数代码如下:
1 void sortArray4(){ 2 3 //首先来3辆车,分别是奥迪、劳斯莱斯、宝马 4 5 Car *car1 = [Car initWithName:@"Audio"]; 6 7 Car *car2 = [Car initWithName:@"Rolls-Royce"]; 8 9 Car *car3 = [Car initWithName:@"BMW"]; 10 11 12 13 //再来5个Person,每人送辆车,分别为car2、car1、car1、car3、car2 14 15 Person *p1 = [Person personWithAge:23 withName:@"zhangsan"withCar:car2]; 16 17 Person *p2 = [Person personWithAge:21 withName:@"zhangsan"withCar:car1]; 18 19 Person *p3 = [Person personWithAge:24 withName:@"lisi"withCar:car1]; 20 21 Person *p4 = [Person personWithAge:23 withName:@"wangwu"withCar:car3]; 22 23 Person *p5 = [Person personWithAge:23 withName:@"wangwu"withCar:car2]; 24 25 26 27 28 29 //加入数组 30 31 NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil]; 32 33 34 35 //构建排序描述器 36 37 NSSortDescriptor *carNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"car.name" ascending:YES]; 38 39 NSSortDescriptor *personNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES]; 40 41 NSSortDescriptor *personAgeDesc = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES]; 42 43 44 45 //把排序描述器放进数组里,放入的顺序就是你想要排序的顺序 46 47 //我这里是:首先按照年龄排序,然后是车的名字,最后是按照人的名字 48 49 NSArray *descriptorArray = [NSArrayarrayWithObjects:personAgeDesc,carNameDesc,personNameDesc, nil]; 50 51 52 53 NSArray *sortedArray = [array sortedArrayUsingDescriptors: descriptorArray]; 54 55 NSLog(@"%@",sortedArray); 56 57 }
结果如下: 从结果看出,先按照age排序,如果age相同,按照car排序,如果car相同,按照name排序。 (注意:上面两种排序方法要想实现字符串显示,请重写description方法) 原博客地址: http://850361034.blog.163.com/blog/static/32803809201436111445914/
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