一、Foundation framework中用於收集cocoa對象（NSObject對象）的三種集合分別是：
NSArray 用於對象有序集合（數組）
NSSet 用於對象無序集合（集合）
NSDictionary用於鍵值映射（字典）
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：這些集合類只能收集cocoa對象（NSOjbect對象），如果想保存一些原始的C數據（例如，int,
float, double, BOOL等），則需要將這些原始的C數據封裝成NSNumber類型的，NSNumber對象是cocoa對象，可以被保存在集合類中。
=================== 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;
//
得到array中的對象個數
-
(id)objectAtIndex:(int)index;
//
得到索引爲i的對象
- (BOOL)containsObject:(id)anObject; // 當anObject出現在array中，則返回yes（實際是通過isEqual:方法來判斷）
- (unsigned)indexOfObject:(id)anObject; // 查找array中的anObject,並返回其最小索引值。沒找到返回NSNotFound.
- (void)makeObjectsPerformSelector:(SEL)aSelector;
-
(NSArray *)sortedArrayUsingSelector:(SEL)aSelector;
- (id)lastObject;
// 得到array中最後一個對象。如果array中沒有任何對象存在，則返回nil
注：
類方法arrayWithObjects 可以創建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];
-----創建數組 -----
NSArray
*array = [[NSArray alloc]
initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
self.dataArray = array;
[array
release];
NSLog(@"self.dataArray count is:%d",[self.dataArray count]);
NSLog(@"self.dataArray index 2 is:%@",[self.dataArray objectAtIndex:2]);
------ 從一個數組拷貝數據到另一數組(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];
=================== NSMutableArray ====================
Mutable version of NSArray.
-
(void)addObject:(id)anObject; //
在array最後添加anObject, 添加nil是非法的.
- (void)addObjectsFromArray:(NSArray
*)otherArray; //在array最後把otherArray中的對象依次添加進去。
- (void)insertObject:(id)anObject atIndex:(int)index; //在索引index處插入anObject, 若index被佔用，會把之後的object向後移。
- (void)removeObjectAtIndex:(int)index; //刪除index處的對象，後面的對象依次向前移。
-
(void)removeObject:(id)anObject;
//
刪除所有和anObject相等的對象，同樣使用isEqual:作爲相等比較方法.
- (void)removeAllObjects;
注：我們不能把nil加到array中。但有時候我們真想給array加一個空的對象，可以使用NSNull來做這件事。如：
[myArray addObject:[NSNull null]];
-----給數組分配容量-----
//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);
-----刪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）-----
//將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要防止內存泄露★------
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，如上面註釋中的語句，才能保證內存不泄露。
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
- (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)removeObject:(id)anObject;
- (void)unionSet:(NSSet *)otherSet;
- (void)minusSet:(NSSet *)otherSet;
- (void)intersectSet:(NSSet *)otherSet;
NSDictionary
- (NSUInteger)hash & - (BOOL)isEqual:(NSObject *)obj
Important methods:
+ dictionaryWithObjectsAndKeys: (id)firstObject, ...;
- (id)objectForKey:(id)key; //返回和key相關聯的value。 如果沒有和key相關聯的value，則返回nil。
- (NSArray *)allKeys; // 返回一個包含所有key的array
- (NSArray *)allValues;
Enumerators 也就是 iterators 或 enumerations.我們可以使用它來一步一步迭代出集合中的所 有成員.
下面是我們可能使用它來列舉所有的 key- ‐vaule
對
NSEnumerator
*e = [myDict
keyEnumerator];
for (NSString *s in e) {
NSLog(@"key is %@, value is %@", s, [myDict objectForKey:s]);
}
注：NSArray 也有一個類似的方法得到 array 的成員迭代 器 : objectEnumerator
- (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];
Mutable version of NSDictionary.
+ (NSMutableDictionary *)dictionary; // 創建一個空的dictionary
- (void)removeObjectForKey:(id)key; // 從dictionary中刪除一條記錄，key以及和它對應的value
- (void)addEntriesFromDictionary:(NSDictionary *)otherDictionary;
//創建
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);
//刪除指定的字典
[dictionary removeObjectForKey:@"3"];
NSLog(@"dictionary:%@",dictionary);