1 int main(int argc, const char * argv[]) { 2     @autoreleasepool { 3         //字典， 存储的内存不是连续的 用key和value进行对应(键值) 4         //kvc 键值编码 5         NSDictionary *dic = [NSDictionary dictionaryWithObject:@"1" forKey:@"a"]; 6         NSLog(@"%@",dic);//以上的方法是不常用的 7         //注意两个参数是数组 8         //NSDictionary *dic2 = [NSDictionary dictionaryWithObjects:<#(NSArray *)#> forKeys:<#(NSArray *)#>] 9         //所以还是要先创建两个数组10         NSArray *array1 = [[NSArray alloc] initWithObjects:@"a",@"b",@"c",@"d", nil];11         NSArray *array2 = [[NSArray alloc] initWithObjects:@"1",@"2",@"3",@"4", nil];12         NSDictionary *dic2 = [[NSDictionary alloc] initWithObjects:array1 forKeys:array2];13         NSLog(@"%@",dic2);14         //15         NSDictionary *dic3 = @{
   @"m":@"9",@"n":@"8"};16         NSLog(@"%@",dic3);17         //输出字典的长度18         int count = (int)[dic3 count];19         NSLog(@"%d",count);20         //通过键 获得 值21         NSString *str = [dic3 valueForKey:@"m"];//或者[dic3 objectForKey:@"m"]22         NSLog(@"%@",str);23         //获取所有键值中的键和值24         NSArray *allValue = [dic3 allValues];25         NSArray *allKey = [dic3 allKeys];26         //通过多个键找值，因为是多个，当然返回的是数组27         NSArray *array = [dic2 objectsForKeys:[NSArray arrayWithObjects:@"2",@"3",@"9", nil] notFoundMarker:@"not found"];28         NSLog(@"%@",array);29         //遍历字典，数组通过下标遍历，字典当然通过key来遍历30         for (NSString *key in dic2) {31             NSLog(@"%@ = %@",key,[dic2 objectForKey:key]);32         }33         //使用针对字典的枚举器34         NSEnumerator *en = [dic2 keyEnumerator];35         id key = nil;36         while (key = [en nextObject]) {37             NSLog(@"key - %@",key);38         }39         //还有一个block方法，用法都是一样的40         /*41         [dic2 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {42             43         }];*/44     }45     return 0;46 }

 

 

1 int main(int argc, const char * argv[]) { 2     @autoreleasepool { 3         NSMutableDictionary *dict = [[NSMutableDictionary alloc] init]; 4         //添加键值对，直接添加就可以了 5         [dict setObject:@"1" forKey:@"a"]; 6         [dict setObject:@"2" forKey:@"b"]; 7         [dict setObject:@"3" forKey:@"c"]; 8         NSLog(@"%@",dict); 9         //删除键值对10         [dict removeObjectForKey:@"a"];11         NSLog(@"%@",dict);12         //还可以通过传入数组对象，对应删除数组元素对应的所有键13         [dict removeObjectsForKeys:[NSArray arrayWithObjects:@"a",@"c", nil]];14         NSLog(@"%@",dict);15     }16     return 0;17 }