On 2016-12-06, Chris Angelico <ros...@gmail.com> wrote:
> On Tue, Dec 6, 2016 at 10:56 PM, BartC <b...@freeuk.com> wrote:
>> In that directory (which was on Windows but accessible via a virtual Linux),
>> typing any Linux command followed by * would have required all 3.4 million
>> directory entries to be accessed in order to build a 3.4 million-element
>> argv list. I've no idea how long that would have taken.
>
> I just asked Python to build me a 4-million-element list, and it took
> no visible time - a small fraction of a second. Don't be afraid of
> large argument lists. We're not writing 8088 Assembly Language
> programs in 64KB of working memory here.
To be fair, literally just now I couldn't run the command I wanted to:
sed -i -e 's/foo/bar/g' /dir/ectory/*.txt
because there were 300,000 files matching the glob, and 'sed' can't
cope with that many command-line arguments. I had to do this instead:
find /dir/ectory -name '*.txt' -exec sed -i -e 's/foo/bar/g' {} \;
(Yes, I could also have done something with 'xargs' instead, which
would've been slower to write and quicker to run.)
However please don't take that to mean I agree with BartC - he's
clearly just reacting with instinctive hostility to the unknown.
--
https://mail.python.org/mailman/listinfo/python-list
