可变字典

NSMutableDictionary *mutdic=[[NSMutableDictionary alloc]initWithObjectsAndKeys:@"Jay",@"name",@"22",@"age",@"F",@"gender",nil];

        //添加

        NSDictionary *dic=[NSDictionary dictionaryWithObject:@"188" forKey:@"height"];

        [mutdic addEntriesFromDictionary:dic];

        [mutdic setValue:@"66" forKey:@"weight"];

        //创建空的可变字典

        NSMutableDictionary *nulldic=[NSMutableDictionary dictionary];

        //将字典newdic设置与字典mutdic对象相同

        [nulldic setDictionary:mutdic];

        //将字典中对应的key的值删除

        [nulldic removeObjectForKey:@"name"];

        NSArray *keys=[NSArray arrayWithObjects:@"height",@"weight", nil];

        [nulldic removeObjectsForKeys:keys];

        //删除全部

        [nulldic removeAllObjects];

        [nulldic setDictionary:mutdic];