
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
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 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 } 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) {
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
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 }
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"];
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];
28
29 //加入数组
30
31 NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil];
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];
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];
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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