iOS開發_Objective-C_數組排序，ios_objective-c

iOS開發_Objective-C_數組排序，ios_objective-c

大體上，OC中常用的數組排序有以下幾種方法：sortedArrayUsingSelector:;sortedArrayUsingComparator:;sortedArrayUsingDescriptors:。

 

1、簡單排序（sortedArrayUsingSelector:）如果只是對字串的排序，可以利用sortedArrayUsingSelector:方法就可以了，代碼如下 

//簡單排序

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(@"排序後:%@",sortedArray);8 9 }

 

 

當然，除了利用字串內建的compare:方法，也可以自己寫compare:方法，進行對象的比較；如下： 首先是建立了 Person 類，實現方法如下（標頭檔就省了）： 

 1 #import "Person.h" 2  3 @implementation Person

 7 //直接實現靜態方法，擷取帶有name和age的Person對象 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 //自訂排序方法24 25 -(NSComparisonResult)comparePerson:(Person *)person{26 27     //預設按年齡排序28 29     NSComparisonResult result = [[NSNumber numberWithInt:person.age]compare:[NSNumber numberWithInt:self.age]];//注意:基礎資料型別 (Elementary Data Type)要進行資料轉換30 31     //如果年齡一樣，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

 

 

主函數代碼如下： 

 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(@"排序後:%@",sortedArray);18 19 }

 

2、利用block文法（sortedArrayUsingComparator:）蘋果官方提供了block文法，比較方便。其中數組排序可以用sortedArrayUsingComparator:方法，代碼如下： 

 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         //這裡的代碼可以參照上面compare:預設的排序方法，也可以把自訂的方法寫在這裡，給對象排序10 11         NSComparisonResult result = [obj1 compare:obj2];12 13         return result;14 15     }];16 17     NSLog(@"排序後:%@",sortedArray);18 19 }

 

    3、進階排序（sortedArrayUsingDescriptors:）如果是這樣一種情況呢？Person類裡有另外一個類的變數，比如說Person類除了name，age變數，還有一輛車Car類型，Car類裡有個name屬性。對Person對象進行排序，有這樣的要求：按照Car的name排序，如果是同一輛車，也就是Car的name相同，那麼再按照年齡進行排序，如果年齡也相同，最後按照Person的name進行排序。 上面這樣就要使用第三種方法，利用排序描述器，不多說，有興趣可以看看API介紹。代碼如下： 首先寫個Car類，實作類別Car.m代碼如下： 

#import "Car.h"@implementation Car
+(Car *)initWithName:(NSString *)name{    Car *car = [[Car alloc] init];    car.name = name;    return car;}@end

 

 

然後改寫Person類，實作類別Person.m代碼如下: 

 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 //這裡重寫description方法，用於最後測試排序結果顯示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

 

 

主函數代碼如下： 

 1 void sortArray4(){ 2  3     //首先來3輛車，分別是奧迪、勞斯萊斯、寶馬 4  5     Car *car1 = [Car initWithName:@"Audio"]; 6  7     Car *car2 = [Car initWithName:@"Rolls-Royce"]; 8  9     Car *car3 = [Car initWithName:@"BMW"];12 13     //再來5個Person，每人送輛車，分別為car2、car1、car1、car3、car214 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     //加入數組30 31     NSArray *array = [NSArray arrayWithObjects:p1,p2,p3,p4,p5, nil];34 35     //構建排序描述器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     //把排序描述器放進數組裡，放入的順序就是你想要排序的順序46 47     //我這裡是：首先按照年齡排序，然後是車的名字，最後是按照人的名字48 49     NSArray *descriptorArray = [NSArrayarrayWithObjects:personAgeDesc,carNameDesc,personNameDesc, nil];

53     NSArray *sortedArray = [array sortedArrayUsingDescriptors: descriptorArray];54 55     NSLog(@"%@",sortedArray);56 57 }

 

 

結果如下：   從結果看出，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：上面兩種排序方法要想實現字串顯示，請重寫description方法）  原部落格地址: http://850361034.blog.163.com/blog/static/32803809201436111445914/

 

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