一、Foundationframework中用于收集cocoa对象（NSObject对象）的三种集合分别是：
NSArray 用于对象有序集合（数组）
NSSet 用于对象无序集合（集合）
NSDictionary用于键值映射（字典）
以上三种集合类是不可变的（一旦初始化后，就不能改变）
以下是对应的三种可变集合类(这三种可变集合类是对应上面三种集合类的子类)：
NSMutableArray
NSMutableSet
NSMutableDictionary
注：这些集合类只能收集cocoa对象（NSOjbect对象），如果想保存一些原始的C数据（例如，int,float, double, BOOL等），则需要将这些原始的C数据封装成NSNumber类型的，NSNumber对象是cocoa对象，可以被保存在集合类中。
=================== NSArray ====================
Ordered collection of objects. Immutable(youcannot add or remove objects to it once it’s created)
Important methods:
+ (id)arrayWithObjects:(id)firstObject,...; // nil terminated
- (int)count; //得到array中的对象个数
-(id)objectAtIndex:(int)index; // 得到索引为i的对象
- (BOOL)containsObject:(id)anObject; //当anObject出现在array中，则返回yes（实际是通过isEqual:方法来判断）
- (unsigned)indexOfObject:(id)anObject; //查找array中的anObject,并返回其最小索引值。没找到返回NSNotFound.
- (void)makeObjectsPerformSelector:(SEL)aSelector;
- (NSArray *)sortedArrayUsingSelector:(SEL)aSelector;
- (id)lastObject; // 得到array中最后一个对象。如果array中没有任何对象存在，则返回nil
注：
类方法arrayWithObjects 可以创建an autoreleased NSArrayof the items.例如
@implementation MyObject
- (NSArray *)coolCats {
return [NSArray arrayWithObjects:@“Steve”, @“Ankush”,@“Sean”, nil];
}
@end
Other convenient create with methods (all return autoreleasedobjects):
[NSString stringWithFormat:@“Meaning of %@ is%d”, @“life”, 42];
[NSDictionary dictionaryWithObjectsAndKeys:ankush,@“TA”, janestudent, @“Student”, nil];
[NSArray arrayWithContentsOfFile:(NSString*)path];
-----创建数组 -----
NSArray*array = [[NSArray alloc]initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
self.dataArray =array;
[arrayrelease];
NSLog(@"self.dataArray count is:%d",[self.dataArraycount]);
NSLog(@"self.dataArray index 2 is:%@",[self.dataArrayobjectAtIndex:2]);
------ 从一个数组拷贝数据到另一数组(可变数级) -------
//arrayWithArray:
NSArray *array1 = [[NSArray alloc] init];
NSMutableArray *MutableArray= [[NSMutableArray alloc] init];
NSArray *array = [NSArrayarrayWithObjects:@"a",@"b",@"c",nil];
NSLog(@"array:%@",array);
MutableArray =[NSMutableArray arrayWithArray:array];
NSLog(@"MutableArray:%@",MutableArray);
array1 = [NSArrayarrayWithArray:array];
NSLog(@"array1:%@",array1);
//Copy
//id obj;
NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArrayarrayWithObjects:@"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];
[newArrayaddObject: obj];
}
NSLog(@"newArray:%@", newArray);
[newArrayrelease];
//快速枚举
NSMutableArray*newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArrayarrayWithObjects:
@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];
NSLog(@"oldArray:%@",oldArray);
for(id obj inoldArray)
{
[newArrayaddObject: obj];
}
NSLog(@"newArray:%@", newArray);
[newArrayrelease];
//Deepcopy
NSMutableArray *newArray = [[NSMutableArray alloc] init];
NSArray *oldArray = [NSArrayarrayWithObjects:
@"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最后添加anObject, 添加nil是非法的.
- (void)addObjectsFromArray:(NSArray*)otherArray; //在array最后把otherArray中的对象依次添加进去。
- (void)insertObject:(id)anObjectatIndex:(int)index; //在索引index处插入anObject,若index被占用，会把之后的object向后移。
-(void)removeObjectAtIndex:(int)index; //删除index处的对象，后面的对象依次向前移。
-(void)removeObject:(id)anObject; //删除所有和anObject相等的对象，同样使用isEqual:作为相等比较方法.
- (void)removeAllObjects;
注：我们不能把nil加到array中。但有时候我们真想给array加一个空的对象，可以使用NSNull来做这件事。如：
[myArrayaddObject:[NSNull null]];
-----给数组分配容量-----
//NSArray*array;
array =[NSMutableArray arrayWithCapacity:20];
-----在数组末尾添加对象-----
//- (void)addObject: (id) anObject;
//NSMutableArray *array =[NSMutableArray arrayWithObjects:@"One",@"Two",@"Three",nil];
[array addObject:@"Four"];
NSLog(@"array:%@",array);
-----删除数组中指定索引处对象-----
//-(void)removeObjectAtIndex: (unsigned) index;
//NSMutableArray *array =[NSMutableArrayarrayWithObjects:@"One",@"Two",@"Three",nil];
[array removeObjectAtIndex:1];
NSLog(@"array:%@",array);
----- 数组枚举-----
//1、- (NSEnumerator*)objectEnumerator; //从前向后
NSMutableArray *array = [NSMutableArrayarrayWithObjects:@"One",@"Two",@"Three",nil];
NSEnumerator*enumerator;
enumerator = [arrayobjectEnumerator];
id thingie;
while (thingie = [enumeratornextObject]) {
NSLog(@"thingie:%@",thingie);
}
//2、- (NSEnumerator*)reverseObjectEnumerator; //从后向前
NSMutableArray *array = [NSMutableArrayarrayWithObjects:@"One",@"Two",@"Three",nil];
NSEnumerator*enumerator;
enumerator = [arrayreverseObjectEnumerator];
id object;
while (object = [enumeratornextObject]) {
NSLog(@"object:%@",object);
}
//3、快速枚举
NSMutableArray *array = [NSMutableArrayarrayWithObjects:@"One",@"Two",@"Three",nil];
for(NSString *string inarray) {
NSLog(@"string:%@",string);
}
----- NSValue（对任何对象进行包装）-----
//将NSRect放入NSArray中
NSMutableArray *array = [[NSMutableArray alloc] init];
NSValue *value;
CGRect rect = CGRectMake(0,0, 320, 480);
value = [NSValuevalueWithBytes:&rectobjCType:@encode(CGRect)];
[arrayaddObject:value];
NSLog(@"array:%@",array);
//从Array中 提取
value = [array objectAtIndex:0];
[valuegetValue:&rect];
NSLog(@"value:%@",value);
----★使用NSMutableArray要防止内存泄露★------
NSObject* p1 = [[NSObject alloc] init];
NSObject* p2 = [[NSObject alloc] init];
NSMutableArray* objectsArray = [[NSMutableArray alloc]init];
[objectsArrayaddObject:p1];
NSLog(@"p1 count:%d", [p1 retainCount]);//输出2，也就是执行追加对象后，对象的计数器也被加1
//[p1 release];
//NSLog(@"p1 count:%d", [p1retainCount]);
//同样做数组替换时
[objectsArray replaceObjectAtIndex:0 withObject:p2];
NSLog(@"p2 count:%d", [p2 retainCount]);//输出 2，同样也是2
NSLog(@"p1 count:%d", [p1retainCount]);//输出 1，对象p1仍然存在
//[p2 release];
//NSLog(@"p2 count:%d", [p2retainCount]);
//执行清空数组
[objectsArray removeAllObjects];
NSLog(@"p2 count:%d", [p2 retainCount]);//输出 1，对象p2仍然存在
//[p2release];
由此可知，每次执行上面的数组操作后，要执行对象release，如上面注释中的语句，才能保证内存不泄露。
NSSet
Unordered collection of objects.
Immutable. You cannot add or remove objects to it once it’screated.
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 matchingobject (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
一个dictionary就是key-value对的集合。 key是字符串（NSString），value是对象指针。
key在整个dictionary是唯一的。通过方法objectForKey：来获得对应于某个key的一个或多个value（值）。
NSDictionary在创建时，其中所有的key和对应的value都存在了。你可以访问其内容，但不可以修改。
dictionary使用hash表来实现，所以查找速度很快。
- (NSUInteger)hash & - (BOOL)isEqual:(NSObject*)obj
Important methods:
+ dictionaryWithObjectsAndKeys: (id)firstObject, ...;
-(int)count; //返回有多少对key-value
-(id)objectForKey:(id)key; //返回和key相关联的value。如果没有和key相关联的value，则返回nil。
-(NSArray *)allKeys; //返回一个包含所有key的array
- (NSArray*)allValues;
- NSEnumerator *)keyEnumerator; //这个方法是从一个 dictionary 中得到一个 key 的迭代器.
Enumerators 也就是iterators 或 enumerations.我们可以使用它来一步一步迭代出集合中的所 有成员.
下面是我们可能使用它来列举所有的 key- ‐vaule 对
NSEnumerator *e = [myDict keyEnumerator];
for (NSString *s in e) {
NSLog(@"key is %@, value is %@", s, [myDict objectForKey:s]);
}
注：NSArray 也有一个类似的方法得到array 的成员迭代 器 : objectEnumerator
-----创建字典 -----
- (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);
[dictionaryrelease];
NSMutableDictionaryMutable version of NSDictionary.
NSMutableDictionary是NSDictionary的子类。创建后，允许用户添加和删除key和value。
+ (NSMutableDictionary *)dictionary; //创建一个空的dictionary
- (void)setObject:(id)anObject forKey:(id)key; //使用key和anObject组成一条记录添加到dictionary中
//如果key已存在，则会先移除旧的key-value，然后再添加新的key-value。
- (void)removeObjectForKey:(id)key; //从dictionary中删除一条记录，key以及和它对应的value
- (void)removeAllObjects;
- (void)addEntriesFromDictionary:(NSDictionary*)otherDictionary;
-----创建可变字典 -----
//创建
NSMutableDictionary*dictionary = [NSMutableDictionarydictionary];
//添加字典
[dictionary setObject:@"One"forKey:@"1"];
[dictionary setObject:@"Two"forKey:@"2"];
[dictionarysetObject:@"Three" forKey:@"3"];
[dictionary setObject:@"Four"forKey:@"4"];
NSLog(@"dictionary:%@",dictionary);
//删除指定的字典
[dictionaryremoveObjectForKey:@"3"];
NSLog(@"dictionary:%@",dictionary);
