how on earth do i get a drive list?

[David Bolen]

"G. Willoughby" <thecalm at NOSPAM.btinternet.com> writes:

> how on earth do i get a drive list? i've been searching for a command to
> display a tuple or list containing all available drives, but i can't find
> it! is it just me or are the standard python docs quite confusing. oh well
> any ideas out there?

Assuming you mean under Windows...

Since the concept of "drives" is an operating-system specific issue,
it's not something in the standard Python libraries, but something
that you generally need to handle in an OS-specific manner.  Sometimes
you'll find such stuff in the os module, but in this case you're
better off with the win32all package which provides interfaces to
windows-specific functions.

win32all is a package that can be installed on top of a stock Python
installation, or in some distributions, like ActiveState, may be
included already.

The simplest method is via the win32api module:

    >>> import win32api
    >>> import string
    >>> string.split(win32api.GetLogicalDriveStrings(),'\0')[:-1]
    ['A:\\', 'C:\\', 'D:\\', 'E:\\']

The actual code is mildly complex, as I'm doing three things at once.
GetLogicalDriveStrings (which is a native Windows function) returns a
single string with the drives separated by NUL characters (\x00).  It
also terminates the list with an extra NUL.

So, I take that string, and then split it on the NULs.  This yields a
list of which the final entry will always be the empty string ('') due
to the extra NUL terminator, so I take a slice of that list to exclude
the final element.

There is also a GetLogicalDrives() that returns a bitmask, which may or
may not be more suitable for your purposes.

Another poster suggested iterating through possible drives using
os.path.exist() which will also work, but will end up activating all
the devices it tries (e.g., your floppy disk may try to be accessed,
and/or the CDROM may spin up briefly), and since the notion of
existence of a drive is platform specific, it's probably worth too
much trying to keep the check platform independent.

--
-- David
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