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总结OC中数组排序3种方法：sortedArrayUsingSelector:;sortedArrayUsingComparator:;sortedArrayUsingDescriptors:
目录[-]
大体上，OC中常用的数组排序有以下几种方法：sortedArrayUsingSelector:;sortedArrayUsingComparator:;sortedArrayUsingDescriptors:
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
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//简单排序void sortArray1(){ NSArray *array = [NSArray arrayWithObjects:@"abc",@"456",@"123",@"789",@"ef", nil]; NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(compare:)]; NSLog(@"排序后:%@",sortedArray);} |
首先是新建了Person类，实现方法如下（头文件就省了）：
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#import "Person.h"@implementation Person//直接实现静态方法，获取带有name和age的Person对象+(Person *)personWithAge:(int) age withName:(NSString *)name{ Person *person = [[Person alloc] init]; person.age = age; person.name = name; return person;}//自定义排序方法-(NSComparisonResult)comparePerson:(Person *)person{ //默认按年龄排序 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 //如果年龄一样，就按照名字排序 if (result == NSOrderedSame) { result = [self.name compare:person.name]; } return result;}@end |
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void sortArray2(){ Person *p1 = [Person personWithAge:23 withName:@"zhangsan"]; Person *p2 = [Person personWithAge:21 withName:@"lisi"]; Person *p3 = [Person personWithAge:24 withName:@"wangwu"]; Person *p4 = [Person personWithAge:24 withName:@"liwu"]; Person *p5 = [Person personWithAge:20 withName:@"liwu"]; NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil]; NSArray *sortedArray = [array sortedArrayUsingSelector:@selector(comparePerson:)]; NSLog(@"排序后:%@",sortedArray);} |
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：
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void sortArray3(){ NSArray *array = [NSArray arrayWithObjects:@"1bc",@"4b6",@"123",@"789",@"3ef", nil]; NSArray *sortedArray = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) { //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 NSComparisonResult result = [obj1 compare:obj2]; return result; }]; NSLog(@"排序后:%@",sortedArray);} |
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：
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#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:
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#import "Person.h"#import "Car.h"@implementation Person+(Person *)personWithAge:(int)age withName:(NSString *)name withCar:(Car *)car{ Person *person = [[Person alloc] init]; person.age = age; person.name = name; person.car = car; return person;}//这里重写description方法，用于最后测试排序结果显示-(NSString *)description{ return [NSString stringWithFormat:@"age is %zi , name is %@, car is %@",_age,_name,_car.name];}@end |
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void sortArray4(){ //首先来3辆车，分别是奥迪、劳斯莱斯、宝马 Car *car1 = [Car initWithName:@"Audio"]; Car *car2 = [Car initWithName:@"Rolls-Royce"]; Car *car3 = [Car initWithName:@"BMW"]; //再来5个Person，每人送辆车，分别为car2、car1、car1、car3、car2 Person *p1 = [Person personWithAge:23 withName:@"zhangsan" withCar:car2]; Person *p2 = [Person personWithAge:21 withName:@"zhangsan" withCar:car1]; Person *p3 = [Person personWithAge:24 withName:@"lisi" withCar:car1]; Person *p4 = [Person personWithAge:23 withName:@"wangwu" withCar:car3]; Person *p5 = [Person personWithAge:23 withName:@"wangwu" withCar:car2]; //加入数组 NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil]; //构建排序描述器 NSSortDescriptor *carNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"car.name" ascending:YES]; NSSortDescriptor *personNameDesc = [NSSortDescriptor sortDescriptorWithKey:@"name" ascending:YES]; NSSortDescriptor *personAgeDesc = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:YES]; //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 //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 NSArray *descriptorArray = [NSArray arrayWithObjects:personAgeDesc,carNameDesc,personNameDesc, nil]; NSArray *sortedArray = [array sortedArrayUsingDescriptors: descriptorArray]; NSLog(@"%@",sortedArray);} |
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）
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原文地址：http://www.cnblogs.com/Peak-Banish/p/4498681.html
