pathlib

Manipulating filesystem paths as string objects can quickly become cumbersome: multiple calls to os.path.join() or os.path.dirname(), etc. This module offers a set of classes featuring all the common operations on paths in an easy, object-oriented way.

This module is best used with Python 3.2 or later, but it is also compatible with Python 2.7. If using it with Python 3.3, you also have access to optional openat-based filesystem operations.

Download

Releases are available on PyPI: http://pypi.python.org/pypi/pathlib/

The development repository and issue tracker can be found at BitBucket: https://bitbucket.org/pitrou/pathlib/

Basic use

Importing the module classes:

>>> from pathlib import *

Listing Python source files in the current directory:

>>> p = Path('.')
>>> [x for x in p if x.ext == '.py']
[PosixPath('test_pathlib.py'), PosixPath('setup.py'),
 PosixPath('pathlib.py')]

Listing subdirectories:

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

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
>>> q.st_mode
33261

Opening a file:

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

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.PurePosixPath

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

>>> PurePosixPath('/etc')
PurePosixPath('/etc')
class pathlib.PureNTPath

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

>>> PureNTPath('c:/Program Files/')
PureNTPath('c:\\Program Files')
class pathlib.PurePath

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

>>> PurePath('setup.py')
PurePosixPath('setup.py')

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.

Constructing paths

Path constructors accept an arbitrary number of positional arguments. When called without any argument, a path object points to the current directory:

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

Any argument can be a string or bytes object representing an arbitrary number of path segments, but it can also be another path object:

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

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')
>>> PureNTPath('c:/Windows', 'd:bar')
PureNTPath('d:bar')

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

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

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
>>> PureNTPath('foo') == PureNTPath('FOO')
True
>>> PureNTPath('FOO') in { PureNTPath('foo') }
True
>>> PureNTPath('C:') < PureNTPath('d:')
True

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

>>> PureNTPath('foo') == PurePosixPath('foo')
False
>>> PureNTPath('foo') < PurePosixPath('foo')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unorderable types: PureNTPath() < PurePosixPath()

Operators

Indexing a path helps create child paths, similarly to os.path.join:

>>> p = PurePath('/etc')
>>> p
PurePosixPath('/etc')
>>> p['passwd']
PurePosixPath('/etc/passwd')
>>> p['init.d/apache2']
PurePosixPath('/etc/init.d/apache2')

The string representation of a path is the raw filesystem path itself, which you can pass to any function taking a file path as a string:

>>> p = PurePath('/etc')
>>> str(p)
'/etc'

Similarly, calling bytes on a path gives the raw filesystem path as a bytes object:

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

Accessing individual parts

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

PurePath.parts

An immutable sequence-like object giving access to the path’s various components. Indexing this object returns individual strings, while slicing this object returns other path objects of the same flavour:

>>> p = PurePath('/usr/bin/python3')
>>> p.parts
<PurePosixPath.parts: ['/', 'usr', 'bin', 'python3']>
>>> p.parts[0]
'/'
>>> p.parts[-1]
'python3'
>>> p.parts[1:]
PurePosixPath('usr/bin/python3')
>>> p.parts[:-1]
PurePosixPath('/usr/bin')

>>> p = PureNTPath('c:/Program Files/PSF')
>>> p.parts[0]
'c:\\'
>>> p.parts[1:]
PureNTPath('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 an properties:

PurePath.drive

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

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

UNC shares are also considered drives:

>>> PureNTPath('//some/share/foo.txt').drive
'\\\\some\\share'
PurePath.root

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

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

UNC shares always have a root:

>>> PureNTPath('//some/share').root
'\\'
PurePath.ext

A string representing the file extension of the final component, if any:

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

UNC drive names are not considered:

>>> PureNTPath('//some/share/setup.py').ext
'.py'
>>> PureNTPath('//some.txt/share.py').ext
''
PurePath.as_bytes()

Equivalent to calling bytes() on the path object:

>>> PurePosixPath('/etc').as_bytes()
b'/etc'
PurePath.as_posix()

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

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

>>> PureNTPath('c:/a/b').is_absolute()
True
>>> PureNTPath('/a/b').is_absolute()
False
>>> PureNTPath('c:').is_absolute()
False
>>> PureNTPath('//some/share').is_absolute()
True
PurePath.is_reserved()

With PureNTPath, return True if the path is considered reserved under Windows, False otherwise. With PurePosixPath, False is always returned.

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

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

PurePath.join(*other)

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

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

>>> PureNTPath('b.py').match('*.PY')
True
PurePath.normcase()

Return a case-folded version of the path. Calling this method is not needed before comparing path objects.

PurePath.parent(level=1)

Return the path’s parent at the level‘th level. If level is not given, return the path’s immediate parent:

>>> p = PurePosixPath('/a/b/c/d')
>>> p.parent()
PurePosixPath('/a/b/c')
>>> p.parent(2)
PurePosixPath('/a/b')
>>> p.parent(3)
PurePosixPath('/a')
>>> p.parent(4)
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 Path.resolve() so as to resolve symlinks and eliminate ”..” components.

PurePath.parents()

Iterate over the path’s parents from the most to the least specific:

>>> for p in PureNTPath('c:/foo/bar/setup.py').parents(): p
...
PureNTPath('c:\\foo\\bar')
PureNTPath('c:\\foo')
PureNTPath('c:\\')
PurePath.relative()

Return the path object stripped of its drive and root, if any:

>>> PurePosixPath('/etc/passwd').relative()
PurePosixPath('etc/passwd')
>>> PurePosixPath('lib/setup.py').relative()
PurePosixPath('lib/setup.py')

>>> PureNTPath('//some/share/setup.py').relative()
PureNTPath('setup.py')
>>> PureNTPath('//some/share/lib/setup.py').relative()
PureNTPath('lib\\setup.py')
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'

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.PosixPath

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

>>> PosixPath('/etc')
PosixPath('/etc')
class pathlib.NTPath

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

>>> NTPath('c:/Program Files/')
NTPath('c:\\Program Files')
class pathlib.Path

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

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

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')
>>> NTPath('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 'NTPath' on your system

Iterating

When a concrete path points to a directory, iterating over it yields path objects of the directory contents:

>>> p = Path('docs')
>>> for child in p: child
...
PosixPath('docs/conf.py')
PosixPath('docs/_templates')
PosixPath('docs/make.bat')
PosixPath('docs/index.rst')
PosixPath('docs/_build')
PosixPath('docs/_static')
PosixPath('docs/Makefile')

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')
Path.stat()

Return information about this path (similarly to os.stat()). The result is cached accross calls.

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

This information can also be accessed through helper attributes.

Path.restat()

Like Path.stat(), but ignores the cached value and always invokes the underlying system call.

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.restat().st_mode
33060
Path.exists()

Whether the path points to an existing file or directory:

>>> from pathlib import *
>>> Path('.').exists()
True
>>> Path('setup.py').exists()
True
>>> Path('/etc').exists()
True
>>> Path('nonexistentfile').exists()
False
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.

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.

Path.is_file()

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

Return True if the path points to a symbolic link, False otherwise.

Path.lchmod(mode)

Like Path.chmod() but, if the path points to a symbolic link, the symbolic link’s mode is changed rather than its target’s.

Path.lstat()

Like Path.stat() but, if the path points to a symbolic link, return the symbolic link’s information rather than its target’s.

Path.mkdir(mode=0o777, parents=False)

Create a new directory at this given path. If mode is given, it is combined with the process’ umask value to determine the file mode and access flags. If the path already exists, OSError is raised.

If parents is True, any missing parents of this path are created as needed. If parents is False (the default), a missing parent raises OSError.

Path.open(mode='r', buffering=-1, encoding=None, errors=None, newline=None)

Open the file pointed to by the path, like the built-in open() function does:

>>> p = Path('setup.py')
>>> with p.open() as f:
...     f.readline()
...
'#!/usr/bin/env python3\n'
Path.raw_open(flags, mode=0o777)

Open the file pointed to by the path and return a numeric file descriptor, as os.open() does:

>>> p = Path('setup.py')
>>> fd = p.raw_open(os.O_RDONLY)
>>> os.read(fd, 10)
b'#!/usr/bin'
>>> os.close(fd)
Path.rename(target)

Rename this file or directory to the given target. target can be either a string or another path object:

>>> p = Path('foo')
>>> p.open('w').write('some text')
9
>>> target = Path('bar')
>>> p.rename(target)
>>> target.open().read()
'some text'
Path.resolve()

Make the path absolute, resolving any symlinks. A new path object is returned:

>>> p = Path()
>>> p
PosixPath('.')
>>> p.resolve()
PosixPath('/home/antoine/pathlib')

”..” components are also eliminated (this is the only method to do so):

>>> p = Path('docs/../setup.py')
>>> p.resolve()
PosixPath('/home/antoine/pathlib/setup.py')

If the path doesn’t exist, an OSError is raised. If an infinite loop is encountered along the resolution path, ValueError is raised.

Path.rglob(pattern)

This is like calling glob() with “**” added in front of the given pattern:

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

Remove this directory. The directory must be empty.

Make this path a symbolic link to target. Under Windows, target_is_directory must be True (default False) if the link’s target is a directory. Under POSIX, target_is_directory‘s value is ignored.

>>> p = Path('mylink')
>>> p.symlink_to('setup.py')
>>> p.resolve()
PosixPath('/home/antoine/pathlib/setup.py')
>>> p.stat().st_size
956
>>> p.lstat().st_size
8

Note

The order of arguments (link, target) is the reverse of os.symlink()‘s.

Path.touch(mode=0o777, exist_ok=True)

Create a file at this given path. If mode is given, it is combined with the process’ umask value to determine the file mode and access flags. If the file already exists, the function succeeds if exist_ok is true, otherwise OSError is raised.

Remove this file or symbolic link. If the path points to a directory, use Path.rmdir() instead.

Attributes

Concrete paths provide the following attributes:

Path.st_mode
Path.st_ino
Path.st_dev
Path.st_uid
Path.st_gid
Path.st_size
Path.st_atime
Path.st_mtime
Path.st_ctime
...

Helper attributes returning the corresponding fields on Path.stat()‘s result:

>>> p = Path('setup.py')
>>> p.st_size
956
>>> p.st_mtime
1327939910.2178059

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