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✏️ Editing: pathlib.rst.txt

:mod:`pathlib` --- Object-oriented filesystem paths
===================================================

.. module:: pathlib
   :synopsis: Object-oriented filesystem paths

.. versionadded:: 3.4

**Source code:** :source:`Lib/pathlib.py`

.. index:: single: path; operations

--------------

This module offers classes representing filesystem paths with semantics
appropriate for different operating systems.  Path classes are divided
between :ref:`pure paths <pure-paths>`, which provide purely computational
operations without I/O, and :ref:`concrete paths <concrete-paths>`, which
inherit from pure paths but also provide I/O operations.

.. image:: pathlib-inheritance.png
   :align: center

If you've never used this module before or just aren't sure which class is
right for your task, :class:`Path` is most likely what you need. It instantiates
a :ref:`concrete path <concrete-paths>` for the platform the code is running on.

Pure paths are useful in some special cases; for example:

#. If you want to manipulate Windows paths on a Unix machine (or vice versa).
   You cannot instantiate a :class:`WindowsPath` when running on Unix, but you
   can instantiate :class:`PureWindowsPath`.
#. You want to make sure that your code only manipulates paths without actually
   accessing the OS. In this case, instantiating one of the pure classes may be
   useful since those simply don't have any OS-accessing operations.

.. seealso::
   :pep:`428`: The pathlib module -- object-oriented filesystem paths.

.. seealso::
   For low-level path manipulation on strings, you can also use the
   :mod:`os.path` module.

Basic use
---------

Importing the main class::

>>> from pathlib import Path

Listing subdirectories::

>>> p = Path('.')
   >>> [x for x in p.iterdir() if x.is_dir()]
   [PosixPath('.hg'), PosixPath('docs'), PosixPath('dist'),
    PosixPath('__pycache__'), PosixPath('build')]

Listing Python source files in this directory tree::

>>> list(p.glob('**/*.py'))
   [PosixPath('test_pathlib.py'), PosixPath('setup.py'),
    PosixPath('pathlib.py'), PosixPath('docs/conf.py'),
    PosixPath('build/lib/pathlib.py')]

Navigating inside a directory tree::

>>> p = Path('/etc')
   >>> q = p / 'init.d' / 'reboot'
   >>> q
   PosixPath('/etc/init.d/reboot')
   >>> q.resolve()
   PosixPath('/etc/rc.d/init.d/halt')

Querying path properties::

>>> q.exists()
   True
   >>> q.is_dir()
   False

Opening a file::

>>> with q.open() as f: f.readline()
   ...
   '#!/bin/bash\n'

.. _pure-paths:

Pure paths
----------

Pure path objects provide path-handling operations which don't actually
access a filesystem.  There are three ways to access these classes, which
we also call *flavours*:

.. class:: PurePath(*pathsegments)

A generic class that represents the system's path flavour (instantiating
   it creates either a :class:`PurePosixPath` or a :class:`PureWindowsPath`)::

>>> PurePath('setup.py')      # Running on a Unix machine
      PurePosixPath('setup.py')

Each element of *pathsegments* can be either a string representing a
   path segment, an object implementing the :class:`os.PathLike` interface
   which returns a string, or another path object::

>>> PurePath('foo', 'some/path', 'bar')
      PurePosixPath('foo/some/path/bar')
      >>> PurePath(Path('foo'), Path('bar'))
      PurePosixPath('foo/bar')

When *pathsegments* is empty, the current directory is assumed::

>>> PurePath()
      PurePosixPath('.')

When several absolute paths are given, the last is taken as an anchor
   (mimicking :func:`os.path.join`'s behaviour)::

>>> PurePath('/etc', '/usr', 'lib64')
      PurePosixPath('/usr/lib64')
      >>> PureWindowsPath('c:/Windows', 'd:bar')
      PureWindowsPath('d:bar')

However, in a Windows path, changing the local root doesn't discard the
   previous drive setting::

>>> PureWindowsPath('c:/Windows', '/Program Files')
      PureWindowsPath('c:/Program Files')

Spurious slashes and single dots are collapsed, but double dots (``'..'``)
   are not, since this would change the meaning of a path in the face of
   symbolic links::

>>> PurePath('foo//bar')
      PurePosixPath('foo/bar')
      >>> PurePath('foo/./bar')
      PurePosixPath('foo/bar')
      >>> PurePath('foo/../bar')
      PurePosixPath('foo/../bar')

(a naïve approach would make ``PurePosixPath('foo/../bar')`` equivalent
   to ``PurePosixPath('bar')``, which is wrong if ``foo`` is a symbolic link
   to another directory)

Pure path objects implement the :class:`os.PathLike` interface, allowing them
   to be used anywhere the interface is accepted.

.. versionchanged:: 3.6
      Added support for the :class:`os.PathLike` interface.

.. class:: PurePosixPath(*pathsegments)

A subclass of :class:`PurePath`, this path flavour represents non-Windows
   filesystem paths::

>>> PurePosixPath('/etc')
      PurePosixPath('/etc')

*pathsegments* is specified similarly to :class:`PurePath`.

.. class:: PureWindowsPath(*pathsegments)

A subclass of :class:`PurePath`, this path flavour represents Windows
   filesystem paths::

>>> PureWindowsPath('c:/Program Files/')
      PureWindowsPath('c:/Program Files')

*pathsegments* is specified similarly to :class:`PurePath`.

Regardless of the system you're running on, you can instantiate all of
these classes, since they don't provide any operation that does system calls.

General properties
^^^^^^^^^^^^^^^^^^

Paths are immutable and hashable.  Paths of a same flavour are comparable
and orderable.  These properties respect the flavour's case-folding
semantics::

>>> PurePosixPath('foo') == PurePosixPath('FOO')
   False
   >>> PureWindowsPath('foo') == PureWindowsPath('FOO')
   True
   >>> PureWindowsPath('FOO') in { PureWindowsPath('foo') }
   True
   >>> PureWindowsPath('C:') < PureWindowsPath('d:')
   True

Paths of a different flavour compare unequal and cannot be ordered::

>>> PureWindowsPath('foo') == PurePosixPath('foo')
   False
   >>> PureWindowsPath('foo') < PurePosixPath('foo')
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
   TypeError: '<' not supported between instances of 'PureWindowsPath' and 'PurePosixPath'

Operators
^^^^^^^^^

The slash operator helps create child paths, similarly to :func:`os.path.join`::

>>> p = PurePath('/etc')
   >>> p
   PurePosixPath('/etc')
   >>> p / 'init.d' / 'apache2'
   PurePosixPath('/etc/init.d/apache2')
   >>> q = PurePath('bin')
   >>> '/usr' / q
   PurePosixPath('/usr/bin')

A path object can be used anywhere an object implementing :class:`os.PathLike`
is accepted::

>>> import os
   >>> p = PurePath('/etc')
   >>> os.fspath(p)
   '/etc'

The string representation of a path is the raw filesystem path itself
(in native form, e.g. with backslashes under Windows), which you can
pass to any function taking a file path as a string::

>>> p = PurePath('/etc')
   >>> str(p)
   '/etc'
   >>> p = PureWindowsPath('c:/Program Files')
   >>> str(p)
   'c:\\Program Files'

Similarly, calling :class:`bytes` on a path gives the raw filesystem path as a
bytes object, as encoded by :func:`os.fsencode`::

>>> bytes(p)
   b'/etc'

.. note::
   Calling :class:`bytes` is only recommended under Unix.  Under Windows,
   the unicode form is the canonical representation of filesystem paths.

Accessing individual parts
^^^^^^^^^^^^^^^^^^^^^^^^^^

To access the individual "parts" (components) of a path, use the following
property:

.. data:: PurePath.parts

A tuple giving access to the path's various components::

>>> p = PurePath('/usr/bin/python3')
      >>> p.parts
      ('/', 'usr', 'bin', 'python3')

>>> p = PureWindowsPath('c:/Program Files/PSF')
      >>> p.parts
      ('c:\\', 'Program Files', 'PSF')

(note how the drive and local root are regrouped in a single part)

Methods and properties
^^^^^^^^^^^^^^^^^^^^^^

Pure paths provide the following methods and properties:

.. data:: PurePath.drive

A string representing the drive letter or name, if any::

>>> PureWindowsPath('c:/Program Files/').drive
      'c:'
      >>> PureWindowsPath('/Program Files/').drive
      ''
      >>> PurePosixPath('/etc').drive
      ''

UNC shares are also considered drives::

>>> PureWindowsPath('//host/share/foo.txt').drive
      '\\\\host\\share'

.. data:: PurePath.root

A string representing the (local or global) root, if any::

>>> PureWindowsPath('c:/Program Files/').root
      '\\'
      >>> PureWindowsPath('c:Program Files/').root
      ''
      >>> PurePosixPath('/etc').root
      '/'

UNC shares always have a root::

>>> PureWindowsPath('//host/share').root
      '\\'

.. data:: PurePath.anchor

The concatenation of the drive and root::

>>> PureWindowsPath('c:/Program Files/').anchor
      'c:\\'
      >>> PureWindowsPath('c:Program Files/').anchor
      'c:'
      >>> PurePosixPath('/etc').anchor
      '/'
      >>> PureWindowsPath('//host/share').anchor
      '\\\\host\\share\\'

.. data:: PurePath.parents

An immutable sequence providing access to the logical ancestors of
   the path::

>>> p = PureWindowsPath('c:/foo/bar/setup.py')
      >>> p.parents[0]
      PureWindowsPath('c:/foo/bar')
      >>> p.parents[1]
      PureWindowsPath('c:/foo')
      >>> p.parents[2]
      PureWindowsPath('c:/')

.. data:: PurePath.parent

The logical parent of the path::

>>> p = PurePosixPath('/a/b/c/d')
      >>> p.parent
      PurePosixPath('/a/b/c')

You cannot go past an anchor, or empty path::

>>> p = PurePosixPath('/')
      >>> p.parent
      PurePosixPath('/')
      >>> p = PurePosixPath('.')
      >>> p.parent
      PurePosixPath('.')

.. note::
      This is a purely lexical operation, hence the following behaviour::

>>> p = PurePosixPath('foo/..')
         >>> p.parent
         PurePosixPath('foo')

If you want to walk an arbitrary filesystem path upwards, it is
      recommended to first call :meth:`Path.resolve` so as to resolve
      symlinks and eliminate `".."` components.

.. data:: PurePath.name

A string representing the final path component, excluding the drive and
   root, if any::

>>> PurePosixPath('my/library/setup.py').name
      'setup.py'

UNC drive names are not considered::

>>> PureWindowsPath('//some/share/setup.py').name
      'setup.py'
      >>> PureWindowsPath('//some/share').name
      ''

.. data:: PurePath.suffix

The file extension of the final component, if any::

>>> PurePosixPath('my/library/setup.py').suffix
      '.py'
      >>> PurePosixPath('my/library.tar.gz').suffix
      '.gz'
      >>> PurePosixPath('my/library').suffix
      ''

.. data:: PurePath.suffixes

A list of the path's file extensions::

>>> PurePosixPath('my/library.tar.gar').suffixes
      ['.tar', '.gar']
      >>> PurePosixPath('my/library.tar.gz').suffixes
      ['.tar', '.gz']
      >>> PurePosixPath('my/library').suffixes
      []

.. data:: PurePath.stem

The final path component, without its suffix::

>>> PurePosixPath('my/library.tar.gz').stem
      'library.tar'
      >>> PurePosixPath('my/library.tar').stem
      'library'
      >>> PurePosixPath('my/library').stem
      'library'

.. method:: PurePath.as_posix()

Return a string representation of the path with forward slashes (``/``)::

>>> p = PureWindowsPath('c:\\windows')
      >>> str(p)
      'c:\\windows'
      >>> p.as_posix()
      'c:/windows'

.. method:: PurePath.as_uri()

Represent the path as a ``file`` URI.  :exc:`ValueError` is raised if
   the path isn't absolute.

>>> p = PurePosixPath('/etc/passwd')
      >>> p.as_uri()
      'file:///etc/passwd'
      >>> p = PureWindowsPath('c:/Windows')
      >>> p.as_uri()
      'file:///c:/Windows'

.. method:: PurePath.is_absolute()

Return whether the path is absolute or not.  A path is considered absolute
   if it has both a root and (if the flavour allows) a drive::

>>> PurePosixPath('/a/b').is_absolute()
      True
      >>> PurePosixPath('a/b').is_absolute()
      False

>>> PureWindowsPath('c:/a/b').is_absolute()
      True
      >>> PureWindowsPath('/a/b').is_absolute()
      False
      >>> PureWindowsPath('c:').is_absolute()
      False
      >>> PureWindowsPath('//some/share').is_absolute()
      True

.. method:: PurePath.is_reserved()

With :class:`PureWindowsPath`, return ``True`` if the path is considered
   reserved under Windows, ``False`` otherwise.  With :class:`PurePosixPath`,
   ``False`` is always returned.

>>> PureWindowsPath('nul').is_reserved()
      True
      >>> PurePosixPath('nul').is_reserved()
      False

File system calls on reserved paths can fail mysteriously or have
   unintended effects.

.. method:: PurePath.joinpath(*other)

Calling this method is equivalent to combining the path with each of
   the *other* arguments in turn::

>>> PurePosixPath('/etc').joinpath('passwd')
      PurePosixPath('/etc/passwd')
      >>> PurePosixPath('/etc').joinpath(PurePosixPath('passwd'))
      PurePosixPath('/etc/passwd')
      >>> PurePosixPath('/etc').joinpath('init.d', 'apache2')
      PurePosixPath('/etc/init.d/apache2')
      >>> PureWindowsPath('c:').joinpath('/Program Files')
      PureWindowsPath('c:/Program Files')

.. method:: PurePath.match(pattern)

Match this path against the provided glob-style pattern.  Return ``True``
   if matching is successful, ``False`` otherwise.

If *pattern* is relative, the path can be either relative or absolute,
   and matching is done from the right::

>>> PurePath('a/b.py').match('*.py')
      True
      >>> PurePath('/a/b/c.py').match('b/*.py')
      True
      >>> PurePath('/a/b/c.py').match('a/*.py')
      False

If *pattern* is absolute, the path must be absolute, and the whole path
   must match::

>>> PurePath('/a.py').match('/*.py')
      True
      >>> PurePath('a/b.py').match('/*.py')
      False

As with other methods, case-sensitivity is observed::

>>> PureWindowsPath('b.py').match('*.PY')
      True

.. method:: PurePath.relative_to(*other)

Compute a version of this path relative to the path represented by
   *other*.  If it's impossible, ValueError is raised::

>>> p = PurePosixPath('/etc/passwd')
      >>> p.relative_to('/')
      PurePosixPath('etc/passwd')
      >>> p.relative_to('/etc')
      PurePosixPath('passwd')
      >>> p.relative_to('/usr')
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
        File "pathlib.py", line 694, in relative_to
          .format(str(self), str(formatted)))
      ValueError: '/etc/passwd' does not start with '/usr'

.. method:: PurePath.with_name(name)

Return a new path with the :attr:`name` changed.  If the original path
   doesn't have a name, ValueError is raised::

>>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
      >>> p.with_name('setup.py')
      PureWindowsPath('c:/Downloads/setup.py')
      >>> p = PureWindowsPath('c:/')
      >>> p.with_name('setup.py')
      Traceback (most recent call last):
        File "<stdin>", line 1, in <module>
        File "/home/antoine/cpython/default/Lib/pathlib.py", line 751, in with_name
          raise ValueError("%r has an empty name" % (self,))
      ValueError: PureWindowsPath('c:/') has an empty name

.. method:: PurePath.with_suffix(suffix)

Return a new path with the :attr:`suffix` changed.  If the original path
   doesn't have a suffix, the new *suffix* is appended instead.  If the
   *suffix* is an empty string, the original suffix is removed::

>>> p = PureWindowsPath('c:/Downloads/pathlib.tar.gz')
      >>> p.with_suffix('.bz2')
      PureWindowsPath('c:/Downloads/pathlib.tar.bz2')
      >>> p = PureWindowsPath('README')
      >>> p.with_suffix('.txt')
      PureWindowsPath('README.txt')
      >>> p = PureWindowsPath('README.txt')
      >>> p.with_suffix('')
      PureWindowsPath('README')

.. _concrete-paths:

Concrete paths
--------------

Concrete paths are subclasses of the pure path classes.  In addition to
operations provided by the latter, they also provide methods to do system
calls on path objects.  There are three ways to instantiate concrete paths:

.. class:: Path(*pathsegments)

A subclass of :class:`PurePath`, this class represents concrete paths of
   the system's path flavour (instantiating it creates either a
   :class:`PosixPath` or a :class:`WindowsPath`)::

>>> Path('setup.py')
      PosixPath('setup.py')

*pathsegments* is specified similarly to :class:`PurePath`.

.. class:: PosixPath(*pathsegments)

A subclass of :class:`Path` and :class:`PurePosixPath`, this class
   represents concrete non-Windows filesystem paths::

>>> PosixPath('/etc')
      PosixPath('/etc')

*pathsegments* is specified similarly to :class:`PurePath`.

.. class:: WindowsPath(*pathsegments)

A subclass of :class:`Path` and :class:`PureWindowsPath`, this class
   represents concrete Windows filesystem paths::

>>> WindowsPath('c:/Program Files/')
      WindowsPath('c:/Program Files')

*pathsegments* is specified similarly to :class:`PurePath`.

You can only instantiate the class flavour that corresponds to your system
(allowing system calls on non-compatible path flavours could lead to
bugs or failures in your application)::

>>> import os
   >>> os.name
   'posix'
   >>> Path('setup.py')
   PosixPath('setup.py')
   >>> PosixPath('setup.py')
   PosixPath('setup.py')
   >>> WindowsPath('setup.py')
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "pathlib.py", line 798, in __new__
       % (cls.__name__,))
   NotImplementedError: cannot instantiate 'WindowsPath' on your system

Methods
^^^^^^^

Concrete paths provide the following methods in addition to pure paths
methods.  Many of these methods can raise an :exc:`OSError` if a system
call fails (for example because the path doesn't exist):

.. classmethod:: Path.cwd()

Return a new path object representing the current directory (as returned
   by :func:`os.getcwd`)::

>>> Path.cwd()
      PosixPath('/home/antoine/pathlib')

.. classmethod:: Path.home()

Return a new path object representing the user's home directory (as
   returned by :func:`os.path.expanduser` with ``~`` construct)::

>>> Path.home()
      PosixPath('/home/antoine')

.. versionadded:: 3.5

.. method:: Path.stat()

Return information about this path (similarly to :func:`os.stat`).
   The result is looked up at each call to this method.

>>> p = Path('setup.py')
      >>> p.stat().st_size
      956
      >>> p.stat().st_mtime
      1327883547.852554

.. method:: Path.chmod(mode)

Change the file mode and permissions, like :func:`os.chmod`::

>>> p = Path('setup.py')
      >>> p.stat().st_mode
      33277
      >>> p.chmod(0o444)
      >>> p.stat().st_mode
      33060

.. method:: Path.exists()

Whether the path points to an existing file or directory::

>>> Path('.').exists()
      True
      >>> Path('setup.py').exists()
      True
      >>> Path('/etc').exists()
      True
      >>> Path('nonexistentfile').exists()
      False

.. note::
      If the path points to a symlink, :meth:`exists` returns whether the
      symlink *points to* an existing file or directory.

.. method:: Path.expanduser()

Return a new path with expanded ``~`` and ``~user`` constructs,
   as returned by :meth:`os.path.expanduser`::

>>> p = PosixPath('~/films/Monty Python')
      >>> p.expanduser()
      PosixPath('/home/eric/films/Monty Python')

.. versionadded:: 3.5

.. method:: Path.glob(pattern)

Glob the given *pattern* in the directory represented by this path,
   yielding all matching files (of any kind)::

>>> sorted(Path('.').glob('*.py'))
      [PosixPath('pathlib.py'), PosixPath('setup.py'), PosixPath('test_pathlib.py')]
      >>> sorted(Path('.').glob('*/*.py'))
      [PosixPath('docs/conf.py')]

The "``**``" pattern means "this directory and all subdirectories,
   recursively".  In other words, it enables recursive globbing::

>>> sorted(Path('.').glob('**/*.py'))
      [PosixPath('build/lib/pathlib.py'),
       PosixPath('docs/conf.py'),
       PosixPath('pathlib.py'),
       PosixPath('setup.py'),
       PosixPath('test_pathlib.py')]

.. note::
      Using the "``**``" pattern in large directory trees may consume
      an inordinate amount of time.

.. method:: Path.group()

Return the name of the group owning the file.  :exc:`KeyError` is raised
   if the file's gid isn't found in the system database.

.. method:: Path.is_dir()

Return ``True`` if the path points to a directory (or a symbolic link
   pointing to a directory), ``False`` if it points to another kind of file.