Version number comparison in Python

by

How about using Python’s distutils.version.StrictVersion?

>>> from distutils.version import StrictVersion
>>> StrictVersion('10.4.10') > StrictVersion('10.4.9')
True

So for your cmp function:

>>> cmp = lambda x, y: StrictVersion(x).__cmp__(y)
>>> cmp("10.4.10", "10.4.11")
-1

If you want to compare version numbers that are more complex distutils.version.LooseVersion will be more useful, however be sure to only compare the same types.

>>> from distutils.version import LooseVersion, StrictVersion
>>> LooseVersion('1.4c3') > LooseVersion('1.3')
True
>>> LooseVersion('1.4c3') > StrictVersion('1.3')  # different types
False

LooseVersion isn’t the most intelligent tool, and can easily be tricked:

>>> LooseVersion('1.4') > LooseVersion('1.4-rc1')
False

To have success with this breed, you’ll need to step outside the standard library and use setuptools‘s parsing utility parse_version.

>>> from pkg_resources import parse_version
>>> parse_version('1.4') > parse_version('1.4-rc2')
True

So depending on your specific use-case, you’ll need to decide whether the builtin distutils tools are enough, or if it’s warranted to add as a dependency setuptools.

More Related Contents:

  1. Comparing a string to multiple items in Python
  2. How do I compare version numbers in Python?
  3. Good Python modules for fuzzy string comparison? [closed]
  4. Checking whether a string starts with XXXX
  5. When to use which fuzz function to compare 2 strings
  6. Python: Why does (“hello” is “hello”) evaluate as True? [duplicate]
  7. String similarity with Python + Sqlite (Levenshtein distance / edit distance)
  8. How can I implement for loop in Python?
  9. Activate a virtualenv with a Python script
  10. Object of custom type as dictionary key
  11. Is it possible to specify your own distance function using scikit-learn K-Means Clustering?
  12. Scrolling to element using webdriver?
  13. Failed to upload packages to PyPI: 410 Gone
  14. Python | accessing dll using ctypes
  15. Serve image stored in SQLAlchemy LargeBinary column
  16. Python json.loads fails with `ValueError: Invalid control character at: line 1 column 33 (char 33)`
  17. How to make unicode string with python3
  18. How to remove multiple items from a list in just one statement?
  19. Is there a way to have a conditional requirements.txt file for my Python application based on platform?
  20. Using request.user with Django ModelForm
  21. Finding the nearest value and return the index of array in Python
  22. How to convert a list of numbers to jsonarray in Python
  23. How do you set a conditional in python based on datatypes?
  24. Turning a list into nested lists in python
  25. setting spacing between grouped bar plots in matplotlib
  26. How to get the first word in the string
  27. Scrapy: ImportError: No module named items
  28. Add image annotations to bar plots
  29. How do I sum tuples in a list where the first value is the same?
  30. Iterate over a string 2 (or n) characters at a time in Python

Leave a Comment