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++)
? ? {? ?? ???
? ?? ???obj = [[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* objectsArray = [[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
? ? //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];
