[Tutor] Zipfile and File manipulation questions.

[Danny Yoo]

> Is there a way to say :
> for filename in zfile.namelist() contains '.txt, .exe':

Hi Chris,

Yes.  It sounds like you want to filter zfile.namelist() and restrict the 
entries to those with particular extensions.  Try a "list comprehension" 
to filter for those interesting filenames:

   for filename in [f for f in zfile.namelist()
                    if os.path.splitext(f)[1] in ('.txt', '.exe')]:

This may be a little dense and hard to read.  So you can always break this 
out into a function:

#########################################################
def keep_txt_exe_filenames(file_list):
     """keep_txt_exe_filenames: list of strings -> list of strings
     Returns a list of all filenames that end in .txt or .exe."""
     return [f for f in file_list
            if os.path.splitext(f)[1] in ('.txt', '.exe')]
#########################################################

At least that tight expression is documented and can be treated as a black 
box.  But after you have this function, you can use that helper function:

    for filename in keep_txt_exe_filenames(zfile.namelist()):
        ...

which is usually fairly easy for a person to understand.


> os.remove('*.txt, *.exe')

One way to approach this is with loops.  You might find the glob module 
useful here:

     http://docs.python.org/lib/module-glob.html

It'll help to match the file names for each glob pattern.  Again, if you 
find yourself doing this a bit, make a helper function to make it easier 
to say next time.  *grin*


Good luck!