how to do a numeric sort

[DeaD_EyE]

I did this in 15 minutes to wake up..

Output:
andre@andre-GP70-2PE:~$ python  by_version.py 
{(2, 4): ['python2.4.1-foo.gz'],
 (3, 4): ['python3.4.0-foo.gz',
          'python-3.4.2-foo.gz',
          'python-3.4.3-foo.gz',
          'python-3.4.4-foo.gz',
          'python-3.4.5-foo.gz',
          'python-3.4.6-foo.gz',
          'python-3.4.7-foo.gz',
          'python-3.4.8-foo.gz',
          'python-3.4.9-foo.gz',
          'python-3.4.10foo.gz'],
 (3, 5): ['python-3.5.0-foo.gz',
          'python-3.5.1-foo.gz',
          'python-3.5.2-foo.gz',
          'python-3.5.3-foo.gz',
          'python-3.5.4-foo.gz',
          'python-3.5.5-foo.gz',
          'python-3.5.6-foo.gz',
          'python-3.5.7-foo.gz']}

import re
from itertools import groupby
from pprint import pprint


pattern = re.compile(r'python-?(\d+)\.(\d+)\.(\d+)-?.+\.gz')


def by_version(version_string):
    match = pattern.search(version_string)
    if match:
        return tuple(int(v) for v in match.groups())
    else:
        return 0, 0, 0


def sort_by_major_minor(versions):
    sorted_versions = sorted(versions, key=by_version)
    result = {}
    for major_group, major in groupby(sorted_versions, key=lambda v: by_version(v)[0]):
        #print('Major', major_group)
        for minor_group, minor in groupby(major, key=lambda v: by_version(v)[1]):
            #print('Minor', minor_group)
            result[(major_group, minor_group)] = list(minor)
    return result
    
    
lst = ['python3.4.0-foo.gz',
       'python2.4.1-foo.gz',
       'python-3.4.10foo.gz',
       'python-3.4.2-foo.gz',
       'python-3.4.3-foo.gz',
       'python-3.4.4-foo.gz',
       'python-3.4.5-foo.gz',
       'python-3.4.6-foo.gz',
       'python-3.4.7-foo.gz',
       'python-3.4.8-foo.gz',
       'python-3.4.9-foo.gz',
       'python-3.5.0-foo.gz',
       'python-3.5.1-foo.gz',
       'python-3.5.2-foo.gz',
       'python-3.5.3-foo.gz',
       'python-3.5.4-foo.gz',
       'python-3.5.5-foo.gz',
       'python-3.5.6-foo.gz',
       'python-3.5.7-foo.gz']


pprint(sort_by_major_minor(lst))

I did it how I would group Major and Minor Versions together.

[Skaperen]

Wouldn't sort --version-sort suit your needs?

for a lot uses, perhaps so. but versions is just one example. i illustrated with versions because it was a familiar example. i do have other cases that may or may not work with version handling programs, depending on how those programs extract or parse and deal with numbers. i just don't know what cases these features work with, so i pursue general solutions that i know will or should. for sort --version-sort the man page only describes it for versions.

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i remember implementing a general case compare function in 360/370 mainframe assembler language decades ago that worked character by character. it checked for decimal digits and counted how many there were to carry out the comparison as if the two numbers being compared were of equal length. Python posed an interesting difference since it used a function that was to return what was to be compared, unlike, for example, C's qsort() that takes a function that is to perform the actual comparison.

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i just found that sort --version-sort changes the collating order of other characters like . and _ which sort higher than alnums with that option. my method does not change the collating order.