NSMutableDictionary的基本使用 - OC

• 可变字典的创建
  //1)可变字典的创建
  NSMutableDictionary *dict1 = [NSMutableDictionary dictionary]; //创建空字典
  NSMutableDictionary *dict2 = [NSMutableDictionary dictionaryWithCapacity:3];

• 增
  [dict1 setValue:@"zhaosi" forKey:@"ls"];//因为key值重复了,所以添加不上
  [dict1 setValue:@"lisi" forKey:@"ls"]; // ls

    [dict1 setValue:@"liuneng" forKey:@"ln"];
    NSLog(@"%@",dict1);
  

• 删
  [dict1 removeObjectForKey:@"ls"];
  //全部删除
  // [dict1 removeAllObjects];

• 改
  [dict1 setObject:@"zhaosi" forKey:@"ls"];
  //简写形式
  dict1[@"ls"] = @"xxxxx";
  NSLog(@"%@",dict1);

• 查
  //获取所有的key值
  NSArray *arr = [dict1 allKeys];
  if([arr containsObject:@"ls"]){

        NSLog(@"存在ls的key");
    }