OC学习(2)-集合

集合的概念

指具有某种特定性质的对象汇总成的集体。这些对象叫集合元素。
比如：整数集{-1，0，1，2}、自然数集{1，2，3，4，5}

• 特点: 确定性 互异性 无序性

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Foundationframework中对象（NSObject）的三种集合

NSSet	NSMutableSet	用于对象无序集合(集合)
NSArray	NSMutableArray	用于对象有序集合(数组)
NSDictionary	NSMutableDictionary	用于键值映射(字典)

注：这些集合类只能容纳cocoa对象（NSOjbect对象）

集合类如何保存基本数据类型

例如：int,float, double, BOOL,struct等。
需要将这些基本数据封装成NSNumber类型进行存储。NSNumber对象是cocoa对象，这样就可以被保存在集合类中。

NSNumber封装对象

  -(NSNumber* )initWithFloat:(float)value;
  -(NSNumber* )initWithDouble:(double)value;
  -(NSNumber* )initWithBool:(BOOL)value ;
  -(NSNumber* )initWithInteger:(NSInteger)value;

NSSet, NSMutableSet

1 集合对象唯一（2个相同对象，无法同时存在）
2 通过hash查询快速，但是无序，杂乱
3 不能确定加入集合后对象的位置
4 数据量大的场合，数据筛选及遍历，建议使用

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集合NSSet声明

对象方法-initWithObjects

NSSet * set = [[NSSet alloc] initWithObjects:@"one”, nil];

类方法-Set

NSSet * set = [NSSetSet];

集合NSMutableSet

1 因NSMutableSet继承NSSet，拥有NSSet方法
2 新增修改，删除，追加函数

集合操作

集合的创建

        NSSet *set1 = [NSSet setWithObjects:@"1",@"2", nil];
        NSSet *set2 = [NSSet setWithObjects:@"3",@"4",@"5",@"6", nil];
        NSArray *array = [NSArray arrayWithObjects:@"6",@"7",@"8", nil];
        NSSet *set3 = [NSSet setWithArray:array];
        NSSet *set4 = [NSSet setWithSet:set1];
        NSSet *set5 = [NSSet setWithObjects:@"1",@"2", nil];
        NSSet *set6 = [NSSet setWithObjects:@"1",@"2",@"6",@"7", nil];

返回数量

        NSInteger count = [set3 count];
        NSLog(@"set3 count = %ld",(long)count);

返回任意对象

        NSString *string = [set3 anyObject];
        NSLog(@"string = %@",string);

返回所有对象

        NSArray *objects = [set3 allObjects];
        NSLog(@"objects = %@",objects);

是否包含

        BOOL isContain = [set3 containsObject:@"6"];
        BOOL isContain1 = [set3 containsObject:@"10"];
        NSLog(@"isContain = %d, isContain1 = %d",isContain, isContain1);

集合间是否存在交集

        BOOL isIntersect = [set2 intersectsSet:set3];
        BOOL isInterset1 = [set1 intersectsSet:set2];
        NSLog(@"isItersect = %ld,isItersect1 = %ld",(long)isIntersect,(long)isInterset1);

集合是否匹配

        BOOL isEqual = [set1 isEqualToSet:set2];
        BOOL isEqual1 = [set1 isEqualToSet:set5];
        NSLog(@"isEqual = %ld,isEqual1 = %ld",(long)isEqual,(long)isEqual1);

结合是否是字子集

        BOOL isSub = [set2 isSubsetOfSet:set3];
        bool isSub1 = [set1 isSubsetOfSet:set6];
        NSLog(@"isSub = %ld, isSub1 = %ld",(long)isSub, (long)isSub1);

集合的添加

        NSSet *set7 = [set5 setByAddingObject:@"One"];
        NSLog(@"set7 = %@",set7);
        NSArray *array1 = [NSArray arrayWithObjects:@"two",@"three",@"four", nil];
        NSSet *set8 = [set7 setByAddingObjectsFromArray:array1];
        NSLog(@"set8 = %@",set8);
        NSSet *set9 = [set8 setByAddingObjectsFromSet:set5];
        NSLog(@"set9 = %@",set9);

可变集合

        NSMutableSet *mutableSet1 = [NSMutableSet set];
        NSMutableSet *mutableSet2 = [NSMutableSet setWithObjects:@"1",@"a", nil];
        NSMutableSet *mutableSet3 = [NSMutableSet setWithObjects:@"2",@"a", nil];
        NSMutableSet *mutableSet4 = [NSMutableSet setWithObjects:@"2",@"a",@"b", nil];
        NSMutableSet *mutableSet5 = [NSMutableSet setWithObjects:@"2",@"a",@"b",@"c",@"d", nil];
        NSLog(@"mutableSet1 = %@",mutableSet1);
        NSLog(@"mutableSet2 = %@",mutableSet2);
        NSLog(@"mutableSet3 = %@",mutableSet3);

一个集合减去另一个集合的元素

        [mutableSet2 minusSet:mutableSet3];
        NSLog(@"mutableSet2 = %@",mutableSet2);

两个集合获取交集部分

        [mutableSet2 intersectSet:mutableSet3];
        NSLog(@"mutableSet2 = %@",mutableSet2);

获取两个集合的并集

        [mutableSet2 unionSet:mutableSet3];
        NSLog(@"mutableSet2 = %@",mutableSet2);

一个集合给另一个集合赋值

        [mutableSet1 setSet:mutableSet3];
        NSLog(@"mutableSet1 = %@",mutableSet1);

删除集合中的对象

        NSLog(@"mutableSet4 = %@",mutableSet4);
        [mutableSet4 removeObject:@"b"];
        NSLog(@"mutableSet4 = %@",mutableSet4);
        [mutableSet4 removeAllObjects];
        NSLog(@"mutableSet4 = %@",mutableSet4);

使用数组的方式进行添加对象

        NSLog(@"mutableSet5 = %@",mutableSet5);
        NSArray *array2 = [NSArray arrayWithObjects:@"e",@"f", nil];
        [mutableSet5 addObjectsFromArray:array2];
        NSLog(@"mutableSet5 = %@",mutableSet5);