如何使用sortedArrayUsingDescriptors對NSMutableArray進行排序？

我有一個關於排序的問題NSMutableArray。我可以使用sortedArrayUsingDescriptors:方法使用對象對數組進行排序。如何使用sortedArrayUsingDescriptors對NSMutableArray進行排序？

比如我的places在那裏我有一個屬性frequency（int值）的NSMutableArray，我要作爲排序依據frequency降，但我不知道如何正確使用它。

作爲鑰匙我在initWithKey上做了什麼？

我的目標place包含：

NSString * name; 
NSString * address; 
NSString * frequency; 
NSString * type;

NSMutableArray * places; 

... populate array with objects ... 

NSSortDescriptor * sortByFrequency = 
    [[[NSSortDescriptor alloc] initWithKey:@"????????" ascending:NO] autorelease]; 

NSArray * descriptors = [NSArray arrayWithObject:sortByFrequency]; 
NSArray * sorted = [x sortedArrayUsingDescriptors:descriptors];

來源

2009-12-04 babyDeveloper

唉！這很難理解。寶貝開發者請在你的問題中使用標點符號（主要是句號和逗號）。 – pmg 2009-12-04 00:24:00

你說這個「frecuency」是一個int值，但你的代碼說它是一個NSString。請注意清楚地說出你的問題。 – Chuck 2009-12-04 00:36:37

下面是如何將排序一個NSMutableArray：

NSMutableArray *numberSort =[[NSMutableArray alloc] init]; 

    while ((key = [enumerator nextObject])) { 
     //(NSNumber *)integer = [key integerValue]; 
     [numberSort addObject:[NSNumber numberWithInt:[key intValue]]]; 
     // code that uses the returned key 
    } 


    NSArray *stringSort = [numberSort sortedArrayUsingSelector:@selector(compare:)]; 
    enumerator = [stringSort objectEnumerator]; 
    NSNumber *intKey; 

    NSMutableArray *backToString =[[NSMutableArray alloc] init]; 

    while ((intKey = [enumerator nextObject])) { 
     //(NSNumber *)integer = [key integerValue]; 
     [backToString addObject:[intKey stringValue]]; 
     // code that uses the returned key

來源

2009-12-04 00:34:56 ennuikiller

「密鑰」是你對象的方法（你的數組「x」）的元素，它返回你想要排序的東西。所以在這種情況下，你說你想按「頻率」排序。然後，你所要做的就是使用返回頻率的方法的名稱作爲鍵。

來源

2009-12-04 00:44:19 newacct

雖然它必須是數字類型，例如'int'（最好是'unsigned'），'NSUInteger'，'double'或'NSNumber *'。以頻率值作爲字符串，它們不會按數字排序（不是沒有自定義比較器，無論如何）。 – 2009-12-05 06:51:16

110

排序你，你的對象數組：

設置NSSortDescriptor - 你的變量作爲鍵設置描述符排序加選擇使用的名稱將在琴鍵上執行
獲得描述符的數組使用NSSortDescriptor你已經設置
排序基於這些描述符

這裏有兩個例子，一個使用陣列NSDictionary和NSString/NSNumber值排序NSNumber，另一個使用自定義類與排序在兩個NSString字段。

按照Sorting and Filtering NSArray Objects在Cocoa編程主題中看到更多的例子和解釋。

例：

這是在GNUstep的做它應該工作一樣可可 - 該代碼是完全一樣的 - 當我坐在我的Mac面前我會嘗試：

NSString * NAME  = @"name"; 
NSString * ADDRESS = @"address"; 
NSString * FREQUENCY = @"frequency"; 
NSString * TYPE  = @"type"; 

NSMutableArray * array = [NSMutableArray array]; 

NSDictionary * dict; 

dict = [NSDictionary dictionaryWithObjectsAndKeys: 
      @"Alehandro", NAME, @"Sydney", ADDRESS, 
      [NSNumber numberWithInt:100], FREQUENCY, 
      @"T", TYPE, nil]; 
[array addObject:dict]; 

dict = [NSDictionary dictionaryWithObjectsAndKeys: 
      @"Xentro", NAME, @"Melbourne", ADDRESS, 
      [NSNumber numberWithInt:50], FREQUENCY, 
      @"X", TYPE, nil]; 
[array addObject:dict]; 

dict = [NSDictionary dictionaryWithObjectsAndKeys: 
      @"John", NAME, @"Perth", ADDRESS, 
      [NSNumber numberWithInt:75], 
      FREQUENCY, @"A", TYPE, nil]; 
[array addObject:dict]; 

dict = [NSDictionary dictionaryWithObjectsAndKeys: 
      @"Fjord", NAME, @"Brisbane", ADDRESS, 
      [NSNumber numberWithInt:20], FREQUENCY, 
      @"B", TYPE, nil]; 
[array addObject:dict];

：使用 NSString和 NSNumber值與 NSNumber值排序

第一示例

排序使用部分描述符與所述頻率字段，它是NSNumber：

NSSortDescriptor * frequencyDescriptor = [[[NSSortDescriptor alloc] initWithKey:FREQUENCY ascending:YES] autorelease]; id obj; NSEnumerator * enumerator = [array objectEnumerator]; while ((obj = [enumerator nextObject])) NSLog(@"%@", obj); NSArray * descriptors = [NSArray arrayWithObjects:frequencyDescriptor, nil]; NSArray * sortedArray = [array sortedArrayUsingDescriptors:descriptors]; NSLog(@"\nSorted ..."); enumerator = [sortedArray objectEnumerator]; while ((obj = [enumerator nextObject])) NSLog(@"%@", obj);

OUTPUT - 用頻域來分類：

2009-12-04 x[1] {address = Sydney; frequency = 100; name = Alehandro; type = T; } 2009-12-04 x[1] {address = Melbourne; frequency = 50; name = Xentro; type = X; } 2009-12-04 x[1] {address = Perth; frequency = 75; name = John; type = A; } 2009-12-04 x[1] {address = Brisbane; frequency = 20; name = Fjord; type = B; } 2009-12-04 x[1] Sorted ... 2009-12-04 x[1] {address = Brisbane; frequency = 20; name = Fjord; type = B; } 2009-12-04 x[1] {address = Melbourne; frequency = 50; name = Xentro; type = X; } 2009-12-04 x[1] {address = Perth; frequency = 75; name = John; type = A; } 2009-12-04 x[1] {address = Sydney; frequency = 100; name = Alehandro; type = T; }

第二個自定義類和對兩個NSString變量進行排序的示例。

數組進行排序（見A類在底部）：

NSMutableArray * array = [NSMutableArray array]; [array addObject:[[A alloc] initWithFirstName:@"Alehandro" lastName:@"Xentro" age:[NSNumber numberWithInt:40]]]; [array addObject:[[A alloc] initWithFirstName:@"John" lastName:@"Smith" age:[NSNumber numberWithInt:30]]]; [array addObject:[[A alloc] initWithFirstName:@"John" lastName:@"Smyth" age:[NSNumber numberWithInt:25]]]; [array addObject:[[A alloc] initWithFirstName:@"Torro" lastName:@"Ola" age:[NSNumber numberWithInt:45]]]; [array addObject:[[A alloc] initWithFirstName:@"Alehandro" lastName:@"Bento" age:[NSNumber numberWithInt:41]]]; [array addObject:[[A alloc] initWithFirstName:@"Alehandro" lastName:@"Axel" age:[NSNumber numberWithInt:41]]];

分揀部，排序按LastName然後姓：

NSString * LASTNAME = @"lastName"; NSString * FIRSTNAME = @"firstName"; NSSortDescriptor *lastDescriptor = [[[NSSortDescriptor alloc] initWithKey:LASTNAME ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)] autorelease]; NSSortDescriptor *firstDescriptor = [[[NSSortDescriptor alloc] initWithKey:FIRSTNAME ascending:YES selector:@selector(localizedCaseInsensitiveCompare:)] autorelease]; NSArray * descriptors = [NSArray arrayWithObjects:lastDescriptor, firstDescriptor, nil]; NSArray * sortedArray = [array sortedArrayUsingDescriptors:descriptors];

打印結果：

NSLog(@"\nSorted ..."); enumerator = [sortedArray objectEnumerator]; while ((obj = [enumerator nextObject])) NSLog(@"%@", obj);

結果（前和排序後）：A延伸NSObject

2009-12-04 00:52:16.637 x[11375] Alehandro, Xentro, age:40 2009-12-04 00:52:16.644 x[11375] John, Smith, age:30 2009-12-04 00:52:16.644 x[11375] John, Smyth, age:25 2009-12-04 00:52:16.644 x[11375] Torro, Ola, age:45 2009-12-04 00:52:16.645 x[11375] Alehandro, Bento, age:41 2009-12-04 00:52:16.645 x[11375] Alehandro, Axel, age:41 2009-12-04 00:52:16.645 x[11375] Sorted ... 2009-12-04 00:52:16.645 x[11375] Alehandro, Axel, age:41 2009-12-04 00:52:16.645 x[11375] Alehandro, Bento, age:41 2009-12-04 00:52:16.645 x[11375] Torro, Ola, age:45 2009-12-04 00:52:16.645 x[11375] John, Smith, age:30 2009-12-04 00:52:16.645 x[11375] John, Smyth, age:25 2009-12-04 00:52:16.645 x[11375] Alehandro, Xentro, age:40

類 - 這裏沒有什麼特別：

#import <Foundation/Foundation.h> @interface A : NSObject { NSString * firstName; NSString * lastName; NSNumber * age; } - (id)initWithFirstName:(NSString*)aFirstName lastName:(NSString*)aLastName age:(NSNumber*)anAge; -(NSString*)description; +(NSString*)action; @end

實現：

#import <Foundation/Foundation.h> #import "A.h" @implementation A - (id)init { return [self initWithFirstName:@"N/A" lastName:@"N/A" age:0]; } - (id)initWithFirstName:(NSString*)aFirstName lastName:(NSString*)aLastName age:(NSNumber*)anAge { self = [super init]; if (!self) return nil; firstName = [aFirstName copy]; lastName = [aLastName copy]; age = [anAge copy]; return self; } - (void)dealloc { [firstName release]; [lastName release]; [age release]; [super release]; }

- (NSString *) description { return [NSString stringWithFormat: @"%@, %@, age:%@", firstName, lastName, age]; } @end

來源

2009-12-04 06:08:11 stefanB

+10

謝謝你這樣詳細的答案！ – DonnaLea 2011-03-09 04:54:09

謝謝你stefanB。非常感謝:) – 2011-05-11 07:14:56

+1，非常感謝Descriptive Answer :)幫了我很多：D – mAc 2012-07-18 14:03:27

如何使用sortedArrayUsingDescriptors對NSMutableArray進行排序？

回答

相關問題