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[OC Foundation框架 - 21] NSSet集合 & 集合之间的转换

A.NSSet
跟NSArray一样,不可变
NSArray 自然顺序
NSSet是无序的
NSSet不允许存入重复元素,可以用来过滤重复元素
 
也有可变的NSMutableSet
 
B.集合转换
       
 1  // 1.NSArray 转换成 NSMutableArray 2         NSArray *array = @[@"one", @"two", @"three"]; 3         NSMutableArray *muArray = [NSMutableArrayarrayWithArray:array]; 4         NSLog(@"muArray = %@", muArray); 5         6         7         // 2.NSDictionary 转换成 NSMutableDictionary 8         NSDictionary *dic = @{@"one":@"1", @"two":@"2", @"three":@"3"}; 9         NSMutableDictionary *muDic = [NSMutableDictionarydictionaryWithDictionary:dic];10         NSLog(@"muDic = %@", muDic);11        12         // 3.NSArray -> NSSet -> NSMutableSet13         NSSet *set = [NSSetsetWithArray:array];14         NSMutableSet *muSet = [NSMutableSetsetWithSet:set];15         NSLog(@"muSet = %@", muSet);16        17         // 4.NSDcitionary -> NSArray18         NSArray *allKeys = [dic allKeys];19         NSLog(@"allKeys = %@", allKeys);20         NSArray *allValues = [dic allValues];21         NSLog(@"allValues = %@", allValues);22        23         // 5.NSString -> NSArray24         NSString *str = @"www.baidu.com";25         NSArray *array2 = [str componentsSeparatedByString:@"."];26         NSLog(@"array2 = %@", array2);
 
 

[OC Foundation框架 - 21] NSSet集合 & 集合之间的转换