OC NSSet

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数组的特点： 有序的
Set的特点： 无序的,存储元素无重复(例:set中有两个元素'a' 输出时只输出一个a)

NSSet初始化

NSSet * set = [[NSSet alloc] initWithObjects:@"a",@"b",@"c", nil];
NSSet * set1 = [NSSet setWithObjects:@"z",@"x",@"c", nil];
NSSet * set2 = [NSSet setWithArray:array];

获取NSSet中任意对象

[set2 anyObject]

是否包含某对象

[set2 containsObject:@"w"]

是否有相同元素

[set intersectsSet:set2]

NSMutableSet用法

NSMutableSet初始化

NSMutableSet * set = [[NSMutableSet alloc] initWithCapacity:0];

追加删除和NSMutableArray一样

取两个NSSet的并集

[set unionSet:set2]

NSSet减去一样的元素

[set minusSet:set2]

取两个NSSet的交集

[set intersectSet:set2]