ios中NSArray,NSSet,NSDictionary总结

//三种集合类来收集cocoa对象(NSObject对象)：

　　NSArray 用于对象有序集合(相当于是数组)

　　NSSet 用于对象无序集合

　　NSDictionary用于键值映射

　　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. 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：

　　类方法arrayWithObjects 可以创建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];

　　-----创建数组 -----

　　//NSArray *array = [[NSArray alloc] initWithObjects:

　　@"One",@"Two",@"Three",@"Four",nil];

　　self.dataArray = array;

　　[array release];

　　//- (unsigned) Count;数组所包含对象个数;

　　NSLog(@"self.dataArray cound:%d",[self.dataArray count]);

　　//- (id) objectAtIndex: (unsigned int) index;获取指定索引处的对象;

　　NSLog(@"self.dataArray cound 2:%@",[self.dataArray objectAtIndex: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 = [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++)

　　{

　　bj = [[oldArray objectAtIndex:i] copy];

　　[newArray addObject: obj];

　　}

　　//

　　NSLog(@"newArray:%@", newArray);

　　[newArray release];

　　//快速枚举

　　//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;

　　-----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 = [NSMutableArray arrayWithObjects:@"One",@"Two",@"Three",nil];

　　[array removeObjectAtIndex:1];

　　NSLog(@"array:%@",array);

　　----- 数组枚举-----

　　//1、- (NSEnumerator *)objectEnumerator; //从前向后

　　//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; //从后向前

　　//NSMutableArray *array = [NSMutableArray arrayWithObjects:

　　@"One",@"Two",@"Three",nil];

　　NSEnumerator *enumerator;

　　enumerator = [array reverseObjectEnumerator];

　　id object;

　　while (object = [enumerator nextObject]) {

　　NSLog(@"object:%@",object);

　　}

　　//3、快速枚举

　　//NSMutableArray *array = [NSMutableArray arrayWithObjects:

　　@"One",@"Two",@"Three",nil];

　　for(NSString *string in array)

　　{

　　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 = [NSValue valueWithBytes:&rect objCType:@encode(CGRect)];

　　[array addObject:value];

　　NSLog(@"array:%@",array);

　　//从Array中 提取

　　value = [array objectAtIndex:0];

　　[value getValue:&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* bjectsArray = [[NSMutableArray alloc] init];

　　[objectsArray addObject: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", [p1 retainCount]);

　　//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", [p1 retainCount]);//输出 1，对象p1仍然存在

　　//[p2 release];

　　//NSLog(@"p2 count:%d", [p2 retainCount]);

　　//执行清空数组

　　[objectsArray removeAllObjects];

　　NSLog(@"p2 count:%d", [p2 retainCount]);//输出 1，对象p2仍然存在

　　//[p2 release];

　　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’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, ..... 一系列键值对。

　　key(键)在整个dictionary是唯一的，通过key可以查询其对应的一个或多个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.

　　- (NSUInteger)hash & - (BOOL)isEqual:(NSObject *)obj

　　Important methods:

　　+ dictionaryWithObjectsAndKeys: (id)firstObject, ...;

　　- (int)count;

　　- (id)objectForKey:(id)key;

　　- (NSArray *)allKeys;

　　- (NSArray *)allValues;

　　-----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);

　　[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;

　　-----创建可变字典 -----

　　//创建

　　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);

　　//删除指定的字典

　　[dictionary removeObjectForKey:@"3"];

　　NSLog(@"dictionary:%@",dictionary);