| 标题 | ios中NSArray,NSSet,NSDictionary总结 |
| 范文 | 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 - (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); |
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