11.1. `pathlib` — Object-oriented filesystem paths¶

Nuevo en la versión 3.4.

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

If you’ve never used this module before or just aren’t sure which class is right for your task, Path is most likely what you need. It instantiates a concrete path 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 WindowsPath when running on Unix, but you can instantiate 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.

Nota

This module has been included in the standard library on a provisional basis. Backwards incompatible changes (up to and including removal of the package) may occur if deemed necessary by the core developers.

Ver también

PEP 428: The pathlib module – object-oriented filesystem paths.

Ver también

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

11.1.1. 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'

11.1.2. 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 pathlib.PurePath(*pathsegments)¶

A generic class that represents the system’s path flavour (instantiating it creates either a PurePosixPath or a 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, 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 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)

class pathlib.PurePosixPath(*pathsegments)¶

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

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

pathsegments is specified similarly to PurePath.

class pathlib.PureWindowsPath(*pathsegments)¶

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

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

pathsegments is specified similarly to 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.

11.1.2.1. 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: unorderable types: PureWindowsPath() < PurePosixPath()

11.1.2.2. Operators¶

The slash operator helps create child paths, similarly to 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')

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 bytes on a path gives the raw filesystem path as a bytes object, as encoded by os.fsencode():

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

Nota

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

11.1.2.3. Accessing individual parts¶

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

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)

11.1.2.4. Methods and properties¶

Pure paths provide the following methods and properties:

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'

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
'\\'

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\\'

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:/')

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('.')

Nota

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 Path.resolve() so as to resolve symlinks and eliminate «..» components.

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
''

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
''

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
[]

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'

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'

PurePath.as_uri()¶

Represent the path as a file URI. 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'

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

PurePath.is_reserved()¶

With PureWindowsPath, return True if the path is considered reserved under Windows, False otherwise. With 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.

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')

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

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'

PurePath.with_name(name)¶

Return a new path with the 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

PurePath.with_suffix(suffix)¶

Return a new path with the suffix changed. If the original path doesn’t have a suffix, the new suffix is appended instead:

>>> 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')

11.1.3. 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 pathlib.Path(*pathsegments)¶

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

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

pathsegments is specified similarly to PurePath.

class pathlib.PosixPath(*pathsegments)¶

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

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

pathsegments is specified similarly to PurePath.

class pathlib.WindowsPath(*pathsegments)¶

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

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

pathsegments is specified similarly to 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

11.1.3.1. Methods¶

Concrete paths provide the following methods in addition to pure paths methods. Many of these methods can raise an 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 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 os.path.expanduser() with ~ construct):

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

Nuevo en la versión 3.5.

Path.stat()¶

Return information about this path (similarly to 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

Path.chmod(mode)¶

Change the file mode and permissions, like os.chmod():

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

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

Nota

If the path points to a symlink, exists() returns whether the symlink points to an existing file or directory.

Path.expanduser()¶

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

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

Nuevo en la versión 3.5.

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')]

Nota

Using the «**» pattern in large directory trees may consume an inordinate amount of time.

Path.group()¶: Return the name of the group owning the file. KeyError is raised if the file’s gid isn’t found in the system database.

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.