ios學習--用法總結：NSArray,NSSet,NSDictionary

三種集合類來收集cocoa對象（NSObject對象）：
NSArray 用於對象有序集合（相當於是數組）
NSSet 用於對象無序集合
NSDictionary用於鍵值映射
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;
- (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：
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];

    //- (unsigned) Count;數組所包含對象個數；
    NSLog(@"self.dataArray cound:%d",[self.dataArray count]);

    //- (id) objectAtIndex: (unsigned int) index;獲取指定索引處的對象;
    NSLog(@"self.dataArray cound 2:%@",[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];   

    //Copy and sort

    //NSMutableArray *newArray = [[NSMutableArray alloc] init];
    NSArray *oldArray = [NSArray arrayWithObjects:

NSMutableArray