[Tutor] How can I copy files recursively?

[Danny Yoo]

> directory structure.  Something like:
>
> source = '/ipodder'
> dest = '/foo/bar'
> for root, dirs, files in os.walk(source):
>    for f in files:
>        os.rename(os.path.join(root, f), os.path.join(dest, f))

A helper function here will be useful.  We can simulate something like:

     find . -name '*.mp3'

with:

#####################################################
import os, fnmatch

def find_with_glob(dir, pattern):
     """find_with_glob: string string -> listof(string)
     Returns a list of all the files that can be found
     in dir or subdirectories, matching the globbing pattern.

     For example: find_with_glob('.', '*.mp3').
     """
     results = []
     for root, dirs, files in os.walk(dir):
         for f in files:
             if fnmatch.fnmatch(f, pattern):
                 results.append(os.path.join(root, f))
     return results
#####################################################

The reason this ends up a bit verbose compared to the shell is because the 
shell's 'find' utility is doing a lot of work too.  But if we were to do a 
simple lookup for mp3 files, I agree that using Unix's 'find' would be the 
simplest approach.

One advantage we have in using Python here is generality: we can, with a 
little work, plug in a different kind of filter here: rather than use 
globs, we can use full-fledged regular expressions.