三種集合類來收集cocoa對象（NSObject對象）：
NSArray 用于對象有序集合（相當于是數組）
NSSet 用于對象無序集合
NSDictionary用于鍵值映射
以上三種集合類是不可變的（一旦初始化後，就不能改變）
以下是對應的三種可變集合類(這三種可變集合類是對應上面三種集合類的子類)：
NSMutableArray
NSMutableSet
NSMutableDictionary
注：這些集合類隻能收集cocoa對象（NSOjbect對象），如果想儲存一些原始的C資料（例如，int, float, double, BOOL等），則需要将這些原始的C資料封裝成NSNumber類型的，NSNumber對象是cocoa對象，可以被儲存在集合類中。
使 NSDictionary 支援NSMutableCopy協定，該協定傳回一個 NSMutableDictionary （這個方法建立的是淺副本，即該新對象擁有源字典所有的對象，它們并不是副本，而是相同的對象）。
NSArray
Ordered collection of objects. Immutable. You cannot add or remove objects to it once it’s created.
Important methods:
+ (id)arrayWithObjects:(id)firstObject, ...; // nil terminated
- (int)count;
- (id)objectAtIndex:(int)index; // NSString *s1=[[myarray objectAtIndex: 0];
- (void)makeObjectsPerformSelector:(SEL)aSelector;
- (NSArray *)sortedArrayUsingSelector:(SEL)aSelector;
- (id)lastObject; // returns nil if there are no objects in the array (convenient)
注：
類方法arrayWithObjects 可以建立an autoreleased NSArray of the items.例如
@implementation MyObject
- (NSArray *)coolCats {
return [NSArray arrayWithObjects:@“Steve”, @“Ankush”, @“Sean”, nil];
}
@end
Other convenient create with methods (all return autoreleased objects):
[NSString stringWithFormat:@“Meaning of %@ is %d”, @“life”, 42];
[NSDictionary dictionaryWithObjectsAndKeys:ankush, @“TA”, janestudent, @“Student”, nil];
[NSArray arrayWithContentsOfFile:(NSString *)path];
-----建立數組 -----
//NSArray *array = [[NSArray alloc] initWithObjects:
@"One",@"Two",@"Three",@"Four",nil];
self.dataArray = array;
[array release];
//- (unsigned) Count;數組所包含對象個數；
NSLog(@"self.dataArray cound:%d",[self.dataArray count]);
//- (id) objectAtIndex: (unsigned int) index;擷取指定索引處的對象;
NSLog(@"self.dataArray cound 2:%@",[self.dataArray objectAtIndex:2]);
------ 從一個數組拷貝資料到另一數組(可變數級) -------
//arrayWithArray:
//NSArray *array1 = [[NSArray alloc] init];
NSMutableArray *MutableArray = [[NSMutableArray alloc] init];
NSArray *array = [NSArray arrayWithObjects:
@"a",@"b",@"c",nil];
NSLog(@"array:%@",array);
MutableArray = [NSMutableArray arrayWithArray:array];
NSLog(@"MutableArray:%@",MutableArray);
array1 = [NSArray arrayWithArray:array];
NSLog(@"array1:%@",array1);
//Copy
//id obj;
NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
NSLog(@"oldArray:%@",oldArray);
for(int i = 0; i < [oldArray count]; i++)
{
obj = [[oldArray objectAtIndex:i] copy];
[newArray addObject: obj];
}
//
NSLog(@"newArray:%@", newArray);
[newArray release];
//快速枚舉
//NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
NSLog(@"oldArray:%@",oldArray);
for(id obj in oldArray)
{
[newArray addObject: obj];
}
//
NSLog(@"newArray:%@", newArray);
[newArray release];
//Deep copy
//NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
NSLog(@"oldArray:%@",oldArray);
newArray = (NSMutableArray*)CFPropertyListCreateDeepCopy(kCFAllocatorDefault, (CFPropertyListRef)oldArray, kCFPropertyListMutableContainers);
NSLog(@"newArray:%@", newArray);
[newArray release];
//Copy and sort
//NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArray arrayWithObjects:
NSMutableArray
Mutable version of NSArray.
- (void)addObject:(id)anObject;
- (void)insertObject:(id)anObject atIndex:(int)index;
- (void)removeObjectAtIndex:(int)index;
- (void)removeAllObjects;
-----給數組配置設定容量-----
//NSArray *array;
array = [NSMutableArray arrayWithCapacity:20];
-----在數組末尾添加對象-----
//- (void) addObject: (id) anObject;
//NSMutableArray *array = [NSMutableArray arrayWithObjects:@"One",@"Two",@"Three",nil];
[array addObject:@"Four"];
NSLog(@"array:%@",array);
-----删除數組中指定索引處對象-----
//-(void) removeObjectAtIndex: (unsigned) index;
//NSMutableArray *array = [NSMutableArray arrayWithObjects:@"One",@"Two",@"Three",nil];
[array removeObjectAtIndex:1];
NSLog(@"array:%@",array);
----- 數組枚舉-----
//1、- (NSEnumerator *)objectEnumerator; //從前向後
//NSMutableArray *array = [NSMutableArray arrayWithObjects:@"One",@"Two",@"Three",nil];
NSEnumerator *enumerator;
enumerator = [array objectEnumerator];
id thingie;
while (thingie = [enumerator nextObject]) {
NSLog(@"thingie:%@",thingie);
}
//2、- (NSEnumerator *)reverseObjectEnumerator; //從後向前
//NSMutableArray *array = [NSMutableArray arrayWithObjects:
@"One",@"Two",@"Three",nil];
NSEnumerator *enumerator;
enumerator = [array reverseObjectEnumerator];
id object;
while (object = [enumerator nextObject]) {
NSLog(@"object:%@",object);
}
//3、快速枚舉
//NSMutableArray *array = [NSMutableArray arrayWithObjects:
@"One",@"Two",@"Three",nil];
for(NSString *string in array)
{
NSLog(@"string:%@",string);
}
----- NSValue（對任何對象進行包裝）-----
//将NSRect放入NSArray中
NSMutableArray *array = [[NSMutableArray alloc] init];
NSValue *value;
CGRect rect = CGRectMake(0, 0, 320, 480);
value = [NSValue valueWithBytes:&rect objCType:@encode(CGRect)];
[array addObject:value];
NSLog(@"array:%@",array);
//從Array中 提取
value = [array objectAtIndex:0];
[value getValue:&rect];
NSLog(@"value:%@",value);
----★使用NSMutableArray要防止記憶體洩露★------
NSObject* p1 = [[NSObject alloc] init];
NSObject* p2 = [[NSObject alloc] init];
NSMutableArray* objectsArray = [[NSMutableArray alloc] init];
[objectsArray addObject:p1];
NSLog(@"p1 count:%d", [p1 retainCount]);//輸出 2，也就是執行追加對象後，對象的計數器也被加1
//[p1 release];
//NSLog(@"p1 count:%d", [p1 retainCount]);
//同樣做數組替換時
[objectsArray replaceObjectAtIndex:0 withObject:p2];
NSLog(@"p2 count:%d", [p2 retainCount]);//輸出 2，同樣也是2
NSLog(@"p1 count:%d", [p1 retainCount]);//輸出 1，對象p1仍然存在
//[p2 release];
//NSLog(@"p2 count:%d", [p2 retainCount]);
//執行清空數組
[objectsArray removeAllObjects];
NSLog(@"p2 count:%d", [p2 retainCount]);//輸出 1，對象p2仍然存在
//[p2 release];
由此可知，每次執行上面的數組操作後，要執行對象release，如上面注釋中的語句，才能保證記憶體不洩露。
NSSet
Unordered collection of objects.
Immutable. You cannot add or remove objects to it once it’s created.
Important methods:
+ setWithObjects:(id)firstObj, ...; // nil terminated
- (int)count;
- (BOOL)containsObject:(id)anObject;
- (id)anyObject;
- (void)makeObjectsPerformSelector:(SEL)aSelector;
- (id)member:(id)anObject; // uses isEqual: and returns a matching object (if any)
NSMutableSet
Mutable version of NSSet.
+ (NSMutableSet *)set; - (void)addObject:(id)anObject;
- (void)removeObject:(id)anObject; - (void)removeAllObjects;
- (void)unionSet:(NSSet *)otherSet;
- (void)minusSet:(NSSet *)otherSet;
- (void)intersectSet:(NSSet *)otherSet;
NSDictionary
key-value, key-value, ..... 一系列鍵值對。
key（鍵）在整個dictionary是唯一的，通過key可以查詢其對應的一個或多個value（值）。 Hash table. Look up objects using a key to get a value.
Immutable. You cannot add or remove objects to it once it’s created.
Keys are objects which must implement. Keys are usually NSString objects. 可使用dictionaryWithObjectsAndKeys來建立字典
查詢字典的值：objectForKey
NSMutableDictionary的dictionary方法可以建立一個可變字典，也可以使用dictionaryWithCapaticy：。
使用 setObject:forkey: 方法添加字典元素，如果關鍵字已存在，則用新植替換舊值。
類似的，NSMutableDictionary類允許随意添加或删除字典元素。
添加元素：setObject:forkey:
删除元素：removeObjectForKey:
- (NSUInteger)hash & - (BOOL)isEqual:(NSObject *)obj
Important methods:
+ dictionaryWithObjectsAndKeys: (id)firstObject, ...; - (int)count;
- (id)objectForKey:(id)key;
- (NSArray *)allKeys;
- (NSArray *)allValues; -----建立字典 -----
//- (id) initWithObjectsAndKeys;
//NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"One",@"1",@"Two",@"2",@"Three",@"3",nil];
NSString *string = [dictionary objectForKey:@"One"];
NSLog(@"string:%@",string);
NSLog(@"dictionary:%@",dictionary);
[dictionary release];
NSMutableDictionary
Mutable version of NSDictionary.
+ (NSMutableDictionary *)dictionary; - (void)setObject:(id)anObject forKey:(id)key;
- (void)removeObjectForKey:(id)key; - (void)removeAllObjects;
- (void)addEntriesFromDictionary:(NSDictionary *)otherDictionary; -----建立可變字典 -----
//建立
NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];
//添加字典
[dictionary setObject:@"One" forKey:@"1"];
[dictionary setObject:@"Two" forKey:@"2"];
[dictionary setObject:@"Three" forKey:@"3"];
[dictionary setObject:@"Four" forKey:@"4"];
NSLog(@"dictionary:%@",dictionary);
//删除指定的字典
[dictionary removeObjectForKey:@"3"];
NSLog(@"dictionary:%@",dictionary);
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