8. Data Types
*************

The modules described in this chapter provide a variety of specialized
data types such as dates and times, fixed-type arrays, heap queues,
synchronized queues, and sets.

Python also provides some built-in data types, in particular, "dict",
"list", "set" and "frozenset", and "tuple".  The "str" class is used
to hold Unicode strings, and the "bytes" class is used to hold binary
data.

本章记录以下模块：

* 8.1. "datetime" --- Basic date and time types

  * 8.1.1. Available Types

  * 8.1.2. "timedelta" Objects

  * 8.1.3. "date" Objects

  * 8.1.4. "datetime" Objects

  * 8.1.5. "time" Objects

  * 8.1.6. "tzinfo" Objects

  * 8.1.7. "timezone" Objects

  * 8.1.8. "strftime()" and "strptime()" Behavior

* 8.2. "calendar" --- General calendar-related functions

* 8.3. "collections" --- Container datatypes

  * 8.3.1. "ChainMap" objects

    * 8.3.1.1. "ChainMap" Examples and Recipes

  * 8.3.2. "Counter" objects

  * 8.3.3. "deque" objects

    * 8.3.3.1. "deque" Recipes

  * 8.3.4. "defaultdict" objects

    * 8.3.4.1. "defaultdict" Examples

  * 8.3.5. "namedtuple()" Factory Function for Tuples with Named
    Fields

  * 8.3.6. "OrderedDict" objects

    * 8.3.6.1. "OrderedDict" Examples and Recipes

  * 8.3.7. "UserDict" objects

  * 8.3.8. "UserList" objects

  * 8.3.9. "UserString" objects

* 8.4. "collections.abc" --- Abstract Base Classes for Containers

  * 8.4.1. Collections Abstract Base Classes

* 8.5. "heapq" --- Heap queue algorithm

  * 8.5.1. Basic Examples

  * 8.5.2. Priority Queue Implementation Notes

  * 8.5.3. Theory

* 8.6. "bisect" --- Array bisection algorithm

  * 8.6.1. Searching Sorted Lists

  * 8.6.2. Other Examples

* 8.7. "array" --- Efficient arrays of numeric values

* 8.8. "weakref" --- 弱引用

  * 8.8.1. Weak Reference Objects

  * 8.8.2. 示例

  * 8.8.3. Finalizer Objects

  * 8.8.4. Comparing finalizers with "__del__()" methods

* 8.9. "types" --- Dynamic type creation and names for built-in
  types

  * 8.9.1. Dynamic Type Creation

  * 8.9.2. Standard Interpreter Types

  * 8.9.3. Additional Utility Classes and Functions

  * 8.9.4. Coroutine Utility Functions

* 8.10. "copy" --- Shallow and deep copy operations

* 8.11. "pprint" --- Data pretty printer

  * 8.11.1. PrettyPrinter Objects

  * 8.11.2. 示例

* 8.12. "reprlib" --- Alternate "repr()" implementation

  * 8.12.1. Repr Objects

  * 8.12.2. Subclassing Repr Objects

* 8.13. "enum" --- Support for enumerations

  * 8.13.1. Module Contents

  * 8.13.2. Creating an Enum

  * 8.13.3. Programmatic access to enumeration members and their
    attributes

  * 8.13.4. Duplicating enum members and values

  * 8.13.5. Ensuring unique enumeration values

  * 8.13.6. Using automatic values

  * 8.13.7. Iteration

  * 8.13.8. Comparisons

  * 8.13.9. Allowed members and attributes of enumerations

  * 8.13.10. Restricted subclassing of enumerations

  * 8.13.11. Pickling

  * 8.13.12. Functional API

  * 8.13.13. Derived Enumerations

    * 8.13.13.1. IntEnum

    * 8.13.13.2. IntFlag

    * 8.13.13.3. Flag

    * 8.13.13.4. Others

  * 8.13.14. Interesting examples

    * 8.13.14.1. Omitting values

      * 8.13.14.1.1. Using "auto"

      * 8.13.14.1.2. Using "object"

      * 8.13.14.1.3. Using a descriptive string

      * 8.13.14.1.4. Using a custom "__new__()"

    * 8.13.14.2. OrderedEnum

    * 8.13.14.3. DuplicateFreeEnum

    * 8.13.14.4. Planet

  * 8.13.15. How are Enums different?

    * 8.13.15.1. Enum Classes

    * 8.13.15.2. Enum Members (aka instances)

    * 8.13.15.3. Finer Points

      * 8.13.15.3.1. Supported "__dunder__" names

      * 8.13.15.3.2. Supported "_sunder_" names

      * 8.13.15.3.3. "Enum" member type

      * 8.13.15.3.4. Boolean value of "Enum" classes and members

      * 8.13.15.3.5. "Enum" classes with methods

      * 8.13.15.3.6. Combining members of "Flag"
