versioning strategies

gistfile1.py

from distutils.version import StrictVersion, LooseVersion

def compare_versions(version1, version2):
    try:
        return cmp(StrictVersion(version1), StrictVersion(version2))
    # in case of abnormal version number, fall back to LooseVersion
    except ValueError:
        return cmp(LooseVersion(version1), LooseVersion(version2))


def highest_version(versions):
    return reduce((lambda v1, v2: compare_versions(v1, v2) == 1 and v1 or v2), versions)

# -------------------------------------------------------
# simpler
from distutils.version import LooseVersion as versioner

class VersionManager(models.Manager):
    def by_version(self, *args, **kwargs):
        qs = self.get_query_set().filter(*args, **kwargs)
        return sorted(qs,key=lambda v: versioner(v.number))