Comparing text strings

[jak]

Il 13/04/2021 01:11, Rich Shepard ha scritto:
> I'm running Slackware64-14.2 and keep a list of installed packages. When a
> package is upgraded I want to remove the earlier version, and I've not
> before written a script like this. Could there be a module or tool that
> already exists to do this? If not, which string function would be best
> suited to the task?
> 
> Here's an example:
> atftp-0.7.2-x86_64-2_SBo.tgz
> atftp-0.7.4-x86_64-1_SBo.tgz
> 
> and there are others like this. I want the python3 script to remove the
> first one. Tools like like 'find' or 'sort -u' won't work because while the
> file name is the same the version or build numbers differ.
> 
> All suggestions welcome.
> 
> Rich
> 

If I understand your problem correctly, the problem would be dealing 
with numbers as such in file names. This is just a track but it might 
help you. This example splits filenames into strings and numbers into 
tuples, appends the tuple into a list, and then sorts the list:

files = ['atftp-0.7.4-x86_64-2_SBo.tgz', 'atftp-0.7.2-x86_64-1_SBo.tgz']
digit = None
da = ''
tfn = tuple()
ltafn = list()
for f in files:
     for c in f:
         if str(c).isdigit():
             if not digit:
                 if len(da) > 0:
                     tfn += (da,)
                     da = ''
                 digit = True
                 da += c
             else:
                 da += c
         else:
             if digit:
                 if len(da) > 0:
                     tfn += (int(da),)
                     da = ''
                 digit = False
                 da += c
             else:
                 da += c
     if len(da) > 0:
         if da.isdigit():
             tfn += (int(da),)
         else:
             tfn += (da,)
         da = ''
     ltafn += [tfn, ]
     tfn = ()

ltafn.sort()

for t in files:
     print(t)
print()
for t in ltafn:
     nn = ''
     for f in t:
         nn += str(f)
     print(nn)