How do I compare version numbers in Python

Question

I am walking a directory that contains eggs to add those eggs to the sys path   If there are two versions of the same  egg in the directory  I want to add only the latest one   I have a regular expression r    P lt eggName gt  w  -  P lt eggVersion gt   d     -    egg  to extract the name and version from the filename   The problem is comparing the version number  which is a string like 2 3 1   Since I m comparing strings  2 sorts above 10  but that s not correct for versions    gt  gt  gt   2 3 1   gt   10 1 1  True   I could do some splitting  parsing  casting to int  etc   and I would eventually get a workaround   But this is Python  not Java   Is there an elegant way to compare version strings

User · Answer

and getting back to easy     for simple scripts you can use  import sys needs    3  9    or whatever pvi   sys version info major  sys version info minor      later in your code try      assert pvi  gt   needs except      print  quot will fail  quot         etc

User · Answer

def versiontuple v       return tuple map int   v split           gt  gt  gt  versiontuple  2 3 1    gt  versiontuple  10 1 1   False

User · Answer

The packaging library contains utilities for working with versions and other packaging-related functionality  This implements PEP 0440 -- Version Identification and is also able to parse versions that don t follow the PEP  It is used by pip  and other common Python tools to provide version parsing and comparison     pip install packaging   from packaging version import parse as parse version version   parse version  1 0 3 dev     This was split off from the original code in setuptools and pkg resources to provide a more lightweight and faster package     Before the packaging library existed  this functionality was  and can still be  found in pkg resources  a package provided by setuptools  However  this is no longer preferred as setuptools is no longer guaranteed to be installed  other packaging tools exist   and pkg resources ironically uses quite a lot of resources when imported  However  all the docs and discussion are still relevant   From the parse version   docs      Parsed a project s version string as defined by PEP 440  The returned value will be an object that represents the version  These objects may be compared to each other and sorted  The sorting algorithm is as defined by PEP 440 with the addition that any version which is not a valid PEP 440 version will be considered less than any valid PEP 440 version and the invalid versions will continue sorting using the original algorithm    The  original algorithm  referenced was defined in older versions of the docs  before PEP 440 existed      Semantically  the format is a rough cross between distutils  StrictVersion and LooseVersion classes  if you give it versions that would work with StrictVersion  then they will compare the same way  Otherwise  comparisons are more like a  smarter  form of LooseVersion  It is possible to create pathological version coding schemes that will fool this parser  but they should be very rare in practice    The documentation provides some examples      If you want to be certain that your chosen numbering scheme works the   way you think it will  you can use the pkg resources parse version     function to compare different version numbers    gt  gt  gt  from pkg resources import parse version  gt  gt  gt  parse version  1 9 a dev      parse version  1 9a0dev   True  gt  gt  gt  parse version  2 1-rc2    lt  parse version  2 1   True  gt  gt  gt  parse version  0 6a9dev-r41475    lt  parse version  0 6a9   True

User · Answer

Posting my full function based on Kindall s solution   I was able to support any alphanumeric characters mixed in with the numbers by padding each version section with leading zeros   While certainly not as pretty as his one-liner function  it seems to work well with alpha-numeric version numbers    Just be sure to set the zfill    value appropriately if you have long strings in your versioning system    def versiontuple v      filled         for point in v split             filled append point zfill 8      return tuple filled        gt  gt  gt  versiontuple  10a 4 5 23-alpha    gt  versiontuple  2a 4 5 23-alpha   True    gt  gt  gt   10a 4 5 23-alpha   gt   2a 4 5 23-alpha  False

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Use packaging version parse   gt  gt  gt  from packaging import version  gt  gt  gt  version parse  quot 2 3 1 quot    lt  version parse  quot 10 1 2 quot   True  gt  gt  gt  version parse  quot 1 3 a4 quot    lt  version parse  quot 10 1 2 quot   True  gt  gt  gt  isinstance version parse  quot 1 3 a4 quot    version Version  True  gt  gt  gt  isinstance version parse  quot 1 3 xy123 quot    version LegacyVersion  True  gt  gt  gt  version Version  quot 1 3 xy123 quot   Traceback  most recent call last       packaging version InvalidVersion  Invalid version   1 3 xy123   packaging version parse is a third-party utility but is used by setuptools  so you probably already have it installed  and is conformant to the current PEP 440  it will return a packaging version Version if the version is compliant and a packaging version LegacyVersion if not  The latter will always sort before valid versions  Note  packaging has recently been vendored into setuptools   An ancient alternative still used by a lot of software is distutils version  built in but undocumented and conformant only to the superseded PEP 386   gt  gt  gt  from distutils version import LooseVersion  StrictVersion  gt  gt  gt  LooseVersion  quot 2 3 1 quot    lt  LooseVersion  quot 10 1 2 quot   True  gt  gt  gt  StrictVersion  quot 2 3 1 quot    lt  StrictVersion  quot 10 1 2 quot   True  gt  gt  gt  StrictVersion  quot 1 3 a4 quot   Traceback  most recent call last       ValueError  invalid version number  1 3 a4   As you can see it sees valid PEP 440 versions as    not strict    and therefore doesn   t match modern Python   s notion of what a valid version is  As distutils version is undocumented  here s the relevant docstrings

User · Answer

I was looking for a solution which wouldn t add any new dependencies  Check out the following  Python 3  solution   class VersionManager        staticmethod     def compare version tuples              major a  minor a  bugfix a              major b  minor b  bugfix b                              Compare two versions a and b  each consisting of 3 integers          compare these as tuples           version a  major a  minor a  bugfix a         version b  major b  minor b  bugfix b           param major a  first part of a          param minor a  second part of a          param bugfix a  third part of a           param major b  first part of b          param minor b  second part of b          param bugfix b  third part of b           return     1 if a   gt  b                     0 if a    b                    -1 if a   lt  b                     tuple a   major a  minor a  bugfix a         tuple b   major b  minor b  bugfix b         if tuple a  gt  tuple b              return 1         if tuple b  gt  tuple a              return -1         return 0       staticmethod     def compare version integers              major a  minor a  bugfix a              major b  minor b  bugfix b                             Compare two versions a and b  each consisting of 3 integers          compare these as integers           version a  major a  minor a  bugfix a         version b  major b  minor b  bugfix b           param major a  first part of a          param minor a  second part of a          param bugfix a  third part of a           param major b  first part of b          param minor b  second part of b          param bugfix b  third part of b           return     1 if a   gt  b                     0 if a    b                    -1 if a   lt  b                       --         if major a  gt  major b              return 1         if major b  gt  major a              return -1           --         if minor a  gt  minor b              return 1         if minor b  gt  minor a              return -1           --         if bugfix a  gt  bugfix b              return 1         if bugfix b  gt  bugfix a              return -1           --         return 0       staticmethod     def test compare versions            functions                  VersionManager compare version tuples   VersionManager compare version tuples                 VersionManager compare version integers   VersionManager compare version integers                      data                   expected result  version a  version b              1  1  0  0  0  0  1                1  1  5  5  0  5  5                1  1  0  5  0  0  5                1  0  2  0  0  1  1                1  2  0  0  1  1  0                0  0  0  0  0  0  0                0  -1  -1  -1  -1  -1  -1      works even with negative version numbers                 0  2  2  2  2  2  2                -1  5  5  0  6  5  0                -1  5  5  0  5  9  0                -1  5  5  5  5  5  6                -1  2  5  7  2  5  8                     count   len data          index   1         for expected result  major a  minor a  bugfix a  major b  minor b  bugfix b in data              for function callback  function name in functions                  actual result   function callback                      major a major a  minor a minor a  bugfix a bugfix a                      major b major b  minor b minor b  bugfix b bugfix b                                    outcome   expected result    actual result                 message                   a          b          expected    actual     format                      index  count                       ok  if outcome is True else  fail                       function name                      major a  minor a  bugfix a                      major b  minor b  bugfix b                      expected result  actual result                                   print message                  assert outcome is True                 index    1           test passed    if   name         main         VersionManager test compare versions     EDIT  added variant with tuple comparison  Of course the variant with tuple comparison is nicer  but I was looking for the variant with integer comparison

User · Answer

What s wrong with transforming the version string into a tuple and going from there  Seems elegant enough for me   gt  gt  gt   2 3 1   lt   10 1 1  True  gt  gt  gt   2 3 1   lt   10 1 1 1  True  gt  gt  gt   2 3 1 10   lt   10 1 1 1  True  gt  gt  gt   10 3 1 10   lt   10 1 1 1  False  gt  gt  gt   10 3 1 10   lt   10 4 1 1  True    kindall s solution is a quick example of how good the code would look

User · Answer

You can use the semver package to determine if a version satisfies a semantic version requirement  This is not the same as comparing two actual versions  but is a type of comparison   For example  version 3 6 0 1234 should be the same as 3 6 0   import semver semver match  3 6 0 1234      3 6 0     True  from packaging import version version parse  3 6 0 1234      version parse  3 6 0     False  from distutils version import LooseVersion LooseVersion  3 6 0 1234      LooseVersion  3 6 0     False

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There is packaging package available  which will allow you to compare versions as per PEP-440  as well as legacy versions    gt  gt  gt  from packaging version import Version  LegacyVersion  gt  gt  gt  Version  1 1    lt  Version  1 2   True  gt  gt  gt  Version  1 2 dev4 deadbeef    lt  Version  1 2   True  gt  gt  gt  Version  1 2 8 5    lt   Version  1 2   False  gt  gt  gt  Version  1 2 8 5    lt   Version  1 2 8 6   True   Legacy version support    gt  gt  gt  LegacyVersion  1 2 8 5-5-gdeadbeef    lt LegacyVersion  1 2 8 5-5-gdeadbeef   gt    Comparing legacy version with PEP-440 version     gt  gt  gt  LegacyVersion  1 2 8 5-5-gdeadbeef    lt  Version  1 2 8 6   True

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The way that setuptools does it  it uses the pkg resources parse version function  It should be PEP440 compliant   Example       usr bin python   - - coding  utf-8 - -    Example comparing two PEP440 formatted versions     import pkg resources  VERSION A   pkg resources parse version  1 0 1-beta 1   VERSION B   pkg resources parse version  v2 67-rc   VERSION C   pkg resources parse version  2 67rc   VERSION D   pkg resources parse version  2 67rc1   VERSION E   pkg resources parse version  1 0 0    print VERSION A  print VERSION B  print VERSION C  print VERSION D   print VERSION A  VERSION B   FALSE print VERSION B  VERSION C   TRUE print VERSION C  VERSION D   FALSE print VERSION A  VERSION E   FALSE

[python] How do I compare version numbers in Python?

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