NSArry,NSSet,NSDictory
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。
使 NSDictionary 支持NSMutableCopy协议,该协议返回一个 NSMutableDictionary (这个方法创建的是浅副本,即该新对象拥有源字典所有的对象,它们并不是副本,而是相同的对象)。
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
- (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)removeObject:(id)anObject;
- (void)unionSet:(NSSet *)otherSet;
- (void)minusSet:(NSSet *)otherSet;
- (void)intersectSet:(NSSet *)otherSet;
NSDictionary
key-value, key-value, ..... 一系列键值对。
Immutable. You cannot add or remove objects to it once it’s created.
Keys are objects which must implement. Keys are usually NSString objects.
查询字典的值:objectForKey
NSMutableDictionary的dictionary方法可以创建一个可变字典,也可以使用dictionaryWithCapaticy:。
使用 setObject:forkey: 方法添加字典元素,如果关键字已存在,则用新植替换旧值。
类似的,NSMutableDictionary类允许随意添加或删除字典元素。
添加元素:setObject:forkey:
删除元素:removeObjectForKey:
- (NSUInteger)hash & - (BOOL)isEqual:(NSObject *)obj
Important methods:
+ dictionaryWithObjectsAndKeys: (id)firstObject, ...;
- (id)objectForKey:(id)key;
- (NSArray *)allKeys;
- (NSArray *)allValues;
//- (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)removeObjectForKey:(id)key;
- (void)addEntriesFromDictionary:(NSDictionary *)otherDictionary;
//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);