NSArray，NSSet等集合类的使用
1，Objective-C 2.0法，最应该使用的
NSArray *aArray; //我们的Array，假设他已经初始化有内容了?for(id innerObj in aArray) //id可以由其他对象类型替代{//也就是说, 在循环中的参数innerObj就是aArray中的对象//由于NSArray中只能储存对象，所以我们使用id作为内涵对象的类型，其实就是个指针了//而且如果NSArray中的内容不一致，id更不会出现冲突}2，C的老方法，不推荐，低性能
NSArray *aArray; //我们的Array，假设他已经初始化有内容了?for(int i=0;i<[aArray count]; i++){[[aArray objectAtIndex:i] 然后作你想作的事情]; //做爱 作的事情...}3, 用NSEnumerator（不知道怎么翻译阿….）
NSEnumerator* myIterator = [myArray reverseObjectEnumerator]; id anObject;? while( anObject = [myIterator nextObject]) //每次读取“逐读器”的下一个对象 { //anObject和刚才的innerObj是一个意思，但是看看多了这么多行 }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];