Version Handling

A core requirement of dealing with packages is the ability to work with versions. PEP 440 defines the standard version scheme for Python packages which has been implemented by this module.

Usage

>>> from packaging.version import Version, parse
>>> v1 = parse("1.0a5")
>>> v2 = Version("1.0")
>>> v1
<Version('1.0a5')>
>>> v2
<Version('1.0')>
>>> v1 < v2
True
>>> v1.epoch
0
>>> v1.release
(1, 0)
>>> v1.pre
('a', 5)
>>> v1.is_prerelease
True
>>> v2.is_prerelease
False
>>> Version("french toast")
Traceback (most recent call last):
    ...
InvalidVersion: Invalid version: 'french toast'
>>> Version("1.0").post
>>> Version("1.0").is_postrelease
False
>>> Version("1.0.post0").post
0
>>> Version("1.0.post0").is_postrelease
True

Reference

packaging.version.parse(version)

This function takes a version string and will parse it as a Version if the version is a valid PEP 440 version, otherwise it will parse it as a LegacyVersion.

class packaging.version.Version(version)

This class abstracts handling of a project’s versions. It implements the scheme defined in PEP 440. A Version instance is comparison aware and can be compared and sorted using the standard Python interfaces.

Parameters

version (str) – The string representation of a version which will be parsed and normalized before use.

Raises

InvalidVersion – If the version does not conform to PEP 440 in any way then this exception will be raised.

public

A string representing the public version portion of this Version().

base_version

A string representing the base version of this Version instance. The base version is the public version of the project without any pre or post release markers.

epoch

An integer giving the version epoch of this Version instance

release

A tuple of integers giving the components of the release segment of this Version instance; that is, the 1.2.3 part of the version number, including trailing zeroes but not including the epoch or any prerelease/development/postrelease suffixes

major

An integer representing the first item of release or 0 if unavailable.

minor

An integer representing the second item of release or 0 if unavailable.

micro

An integer representing the third item of release or 0 if unavailable.

local

A string representing the local version portion of this Version() if it has one, or None otherwise.

pre

If this Version instance represents a prerelease, this attribute will be a pair of the prerelease phase (the string "a", "b", or "rc") and the prerelease number (an integer). If this instance is not a prerelease, the attribute will be None.

is_prerelease

A boolean value indicating whether this Version instance represents a prerelease and/or development release.

dev

If this Version instance represents a development release, this attribute will be the development release number (an integer); otherwise, it will be None.

is_devrelease

A boolean value indicating whether this Version instance represents a development release.

post

If this Version instance represents a postrelease, this attribute will be the postrelease number (an integer); otherwise, it will be None.

is_postrelease

A boolean value indicating whether this Version instance represents a post-release.

class packaging.version.LegacyVersion(version)

This class abstracts handling of a project’s versions if they are not compatible with the scheme defined in PEP 440. It implements a similar interface to that of Version.

This class implements the previous de facto sorting algorithm used by setuptools, however it will always sort as less than a Version instance.

Parameters

version (str) – The string representation of a version which will be used as is.

Note

LegacyVersion instances are always ordered lower than Version instances.

>>> from packaging.version import Version, LegacyVersion
>>> v1 = Version("1.0")
>>> v2 = LegacyVersion("1.0")
>>> v1 > v2
True
>>> v3 = LegacyVersion("1.3")
>>> v1 > v3
True

Also note that some strings are still valid PEP 440 strings (Version), even if they look very similar to other versions that are not (LegacyVersion). Examples include versions with Pre-release spelling and Post-release spelling.

>>> from packaging.version import parse
>>> v1 = parse('0.9.8a')
>>> v2 = parse('0.9.8beta')
>>> v3 = parse('0.9.8r')
>>> v4 = parse('0.9.8rev')
>>> v5 = parse('0.9.8t')
>>> v1
<Version('0.9.8a0')>
>>> v1.is_prerelease
True
>>> v2
<Version('0.9.8b0')>
>>> v2.is_prerelease
True
>>> v3
<Version('0.9.8.post0')>
>>> v3.is_postrelease
True
>>> v4
<Version('0.9.8.post0')>
>>> v4.is_postrelease
True
>>> v5
<LegacyVersion('0.9.8t')>
>>> v5.is_prerelease
False
>>> v5.is_postrelease
False

public

A string representing the public version portion of this LegacyVersion. This will always be the entire version string.

base_version

A string representing the base version portion of this LegacyVersion instance. This will always be the entire version string.

epoch

This will always be -1 since without PEP 440 we do not have the concept of version epochs. The value reflects the fact that LegacyVersion instances always compare less than Version instances.

release

This will always be None since without PEP 440 we do not have the concept of a release segment or its components. It exists primarily to allow a LegacyVersion to be used as a stand in for a Version.

local

This will always be None since without PEP 440 we do not have the concept of a local version. It exists primarily to allow a LegacyVersion to be used as a stand in for a Version.

pre

This will always be None since without PEP 440 we do not have the concept of a prerelease. It exists primarily to allow a LegacyVersion to be used as a stand in for a Version.

is_prerelease

A boolean value indicating whether this LegacyVersion represents a prerelease and/or development release. Since without PEP 440 there is no concept of pre or dev releases this will always be False and exists for compatibility with Version.

dev

This will always be None since without PEP 440 we do not have the concept of a development release. It exists primarily to allow a LegacyVersion to be used as a stand in for a Version.

is_devrelease

A boolean value indicating whether this LegacyVersion represents a development release. Since without PEP 440 there is no concept of dev releases this will always be False and exists for compatibility with Version.

post

This will always be None since without PEP 440 we do not have the concept of a postrelease. It exists primarily to allow a LegacyVersion to be used as a stand in for a Version.

is_postrelease

A boolean value indicating whether this LegacyVersion represents a post-release. Since without PEP 440 there is no concept of post-releases this will always be False and exists for compatibility with Version.

exception packaging.version.InvalidVersion

Raised when attempting to create a Version with a version string that does not conform to PEP 440.

packaging.version.VERSION_PATTERN

A string containing the regular expression used to match a valid version. The pattern is not anchored at either end, and is intended for embedding in larger expressions (for example, matching a version number as part of a file name). The regular expression should be compiled with the re.VERBOSE and re.IGNORECASE flags set.