immutable objects是什么
时间: 2024-02-26 10:21:02 浏览: 34
Immutable objects是指在创建后无法被修改的对象。这些对象的值和状态在创建时就被确定,并且在整个程序运行期间保持不变。常见的immutable objects包括字符串、元组和数字等基本数据类型。相反,可变对象的值和状态可以在创建后进行修改,这些对象在程序运行过程中可能会发生变化,例如列表和字典等数据结构。由于immutable objects的值是不可变的,因此它们在多线程和并发编程等环境中更加安全和可靠。
相关问题
Can not deserialize instance of scala.collection.immutable.List$ out of START_ARRAY token
This error message typically occurs when you are trying to deserialize a JSON array into a Scala List using a library such as Jackson or Gson. The error message is telling you that the library is expecting a JSON object but instead, it is receiving a JSON array.
To fix this issue, you need to ensure that the JSON data is in the correct format for deserialization. If you are using Jackson, you can annotate the field or constructor parameter with @JsonDeserialize(as = List.class) to explicitly tell the library to deserialize the JSON array into a List. If you are using Gson, you can use the TypeToken class to specify the type of the object you want to deserialize.
Another possible solution is to modify the JSON data to match the expected format for deserialization. For example, if you have an array of objects, you can wrap it in a JSON object with a key that represents the name of the array. This will allow you to deserialize the JSON data into a map, where the key maps to a List of objects.
python object cannot be re-sized
This statement is not entirely true. In Python, some objects are immutable, which means they cannot be resized or modified once they are created. Examples of immutable objects include integers, floats, tuples, and strings. On the other hand, some objects are mutable, which means they can be resized or modified after they are created. Examples of mutable objects include lists, dictionaries, and sets.
However, it is important to note that even mutable objects have some limitations on their resizing capabilities. For example, if a list is resized frequently, it can lead to performance issues due to the need for frequent memory reallocations. Therefore, it is important to consider the trade-offs between mutable and immutable objects when designing a program.
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