On 20 August 2015 at 18:25, Alan Gauld <alan.ga...@btinternet.com> wrote:
> On 20/08/15 04:03, Srihari Vijayaraghavan wrote:
>
>> out = sys.stdout.write
>> for root, dirs, files in os.walk("/"):
>> out("The dirs before removing mount points: %s\n" % dirs)
>> for d in dirs:
>> dname = os.path.join(root, d)
>> if os.path.ismount(dname):
>> dirs.remove(d)
>
>
> It's never a good idea to remove items from the thing
> you are iterating over. Create a copy of dirs (dirs[:])
> to iterate on then remove the items from the original
> dirs.
In general I agree, but this is what the os.walk() document states:
"... When topdown is True, the caller can modify the dirnames list
in-place (perhaps using del or slice assignment)..."
(Yes, the topdown argument of os.walk() is True by default, until
manually modified.)
Therefore I see no problem with in-place modification of dirnames.
I've made a copy of dirs & iterated over it, which made no difference
in my case.
My issue is that some of the virtual or in memory file systems' mount
points (like /proc, /dev) are failing to be recognised properly under
os.path.ismount(). Perhaps this quirkiness is irresolvable??
Thank you.
Srihari Vijayaraghavan
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