| Server IP : 188.40.95.74 / Your IP : 216.73.216.205 Web Server : Apache System : Linux cp01.striminghost.net 3.10.0-1160.119.1.el7.tuxcare.els13.x86_64 #1 SMP Fri Nov 22 06:29:45 UTC 2024 x86_64 User : vlasotin ( 1054) PHP Version : 5.6.40 Disable Function : NONE MySQL : ON | cURL : ON | WGET : ON | Perl : ON | Python : ON | Sudo : ON | Pkexec : ON Directory : /usr/share/doc/python-docs-2.7.5/html/_sources/library/ |
Upload File : |
.. _built-in-consts:
Built-in Constants
==================
A small number of constants live in the built-in namespace. They are:
.. data:: False
The false value of the :class:`bool` type.
.. versionadded:: 2.3
.. data:: True
The true value of the :class:`bool` type.
.. versionadded:: 2.3
.. data:: None
The sole value of :attr:`types.NoneType`. ``None`` is frequently used to
represent the absence of a value, as when default arguments are not passed to a
function.
.. versionchanged:: 2.4
Assignments to ``None`` are illegal and raise a :exc:`SyntaxError`.
.. data:: NotImplemented
Special value which can be returned by the "rich comparison" special methods
(:meth:`__eq__`, :meth:`__lt__`, and friends), to indicate that the comparison
is not implemented with respect to the other type.
.. data:: Ellipsis
Special value used in conjunction with extended slicing syntax.
.. data:: __debug__
This constant is true if Python was not started with an :option:`-O` option.
See also the :keyword:`assert` statement.
.. note::
The names :data:`None` and :data:`__debug__` cannot be reassigned
(assignments to them, even as an attribute name, raise :exc:`SyntaxError`),
so they can be considered "true" constants.
.. versionchanged:: 2.7
Assignments to ``__debug__`` as an attribute became illegal.
Constants added by the :mod:`site` module
-----------------------------------------
The :mod:`site` module (which is imported automatically during startup, except
if the :option:`-S` command-line option is given) adds several constants to the
built-in namespace. They are useful for the interactive interpreter shell and
should not be used in programs.
.. data:: quit([code=None])
exit([code=None])
Objects that when printed, print a message like "Use quit() or Ctrl-D
(i.e. EOF) to exit", and when called, raise :exc:`SystemExit` with the
specified exit code.
.. data:: copyright
license
credits
Objects that when printed, print a message like "Type license() to see the
full license text", and when called, display the corresponding text in a
pager-like fashion (one screen at a time).