sorting pathnames by basename

[Erik Price]

I respond to Michael O'Donnell, Kevin Clark, Ben Scott, and 
pll at lanminds.com in this response:


Michael O'Donnell wrote:

> Wow.  That doesn't suck.  Thanks!

Well, I wrote it in a text editor called BBEdit on Mac OS X.  BBEdit's 
advert blurb is, literally: "It doesn't suck" (http://barebones.com/).  
Which I agree with wholeheartedly, it is my favorite programming 
environment.

Kevin Clark wrote:

> One-liners are not representitive of the readability of Perl code.  I
> hope you agree.

Definitely.  Perhaps those who are new to Perl don't quite see it yet 
(although I admit that I am still new to Perl), but I find that the 
one-liners are very elegant and spare me the bother of dropping into an 
editor for something so simple.  Like writing some bash code right there 
on the command line.

For that matter, I have to defer to Kevin's one-liner as it was 
definitely more elegant than the Python code.  I only posted it because 
he asked for it!

Kevin Clark also wrote:

> Can any of the Python programmers on this list implement this as a
> one-liner?  Just wondering.
>
> (with Python's indentation rules, I think that this would be difficult)

It's antithetical to the Python Way.  JAPHs like elegant and terse 
one-liners, but Pythoneers generally don't or can't use them.  Larry 
Wall wrote Perl so that there is more than one way to do everything, 
including coding style (use strict or english, etc).  Python's 
philosophy is "there should generally be one obvious way to do 
something" even if that isn't the most efficient-looking code.

Kevin Clark finally added:

> OBTW, while I appreciate Erik's effort (because, in fact, I am
> learning Python), in actuality, I believe that his program contains a
> bug

Good point!  That Python script was a "five-minuter".  If I had written 
it properly, it should have taken this into account, and also been 
written as a module so that it could itself be reimplemented in other 
code later ("import basenamesort.py").  Also, instead of being limited 
to just a filter for standard input, it would also have had the ability 
to be executed directly as a standalone program, perhaps with an 
argument passed to it ("filenames.txt" or something).  That would have 
made it a "proper" modular Python script, but I fell asleep during 
"Clash of the Titans" at a friends' house a short while before , and I 
just wanted to check/respond to email before I went to bed.  Of course a 
Python script could be written to accommodate these extra functions.

Ben Scott wrote:

> Without even knowing anything about Python,
> I suspect that code could be made denser, by eliminating temporary 
> variables
> and nesting things instead.

Actually, I tried to write it more densely but couldn't.  I'm not a 
Python guru by any stretch, but I had thought that I could use "for key 
in sorted.sort()" instead of having the sort() method call on a separate 
line.  Apparently I can't.  I've been spending a LOT more time learning 
Perl than Python, lately (b/c I'm unemployed and there are dozens more 
Perl jobs than Python jobs out there right now).

Ben Scott also wrote:

>   This is an accident.  In general, Perl was not designed -- it evolved.
> It started small, and then creeping featurism ran rampant on it.  Much 
> like
> Unix, there are a great many things in Perl that don't make a lot of 
> sense
> unless you know the history behind them.

That's right!  Don't forget that Perl 6 is (supposed to be) completely 
redesigned from scratch for this very reason.

pll at lanminds.com wrote:

> Is Python also a "text-munging" type language aimed at sysadmin type
> problems?  Was it too, specifically designed to pick up where awk
> and sed fell short?

Guido van Rossum originally wrote the language specifically for 
educational purposes, because of all of the shortcomings of BASIC.  He 
wanted a fully object-oriented language that be difficult for 
programmers to develop bad habits from (note the lack of a GOTO, and the 
strict enforcement of whitespace and indenting).  This is why Python has 
a nice interactive interpreter -- for real-time experimentation.  Of 
course, programmers like the interactive interpreter because they can 
whip up a function or class definition and then play with it to see how 
it interacts with their code without having to execute an entire script, 
getting immediate feedback on their work.

While I have seen some system-administration stuff written in Python, 
there isn't much.  For one, Perl is far more widely-used and installed 
on more systems.  Also, if I had to do extensive text munging, there is 
no question that I would use Perl to do it over Python unless I had some 
compelling reason not to.  (This is just my opinion, but) Perl's 
text-munging abilities are more convenient to use than Python's.  It's 
like, they're built into the syntax and mentality of Perl, whereas with 
Python you will probably end up importing a module like the string 
module and then executing various methods of the String object (or 
aggregating the String object into a custom-made, more powerful object 
and calling its methods), just like you would with any other task in 
Python.

In conclusion, I don't want to oversimplify things, but I'm going to 
anyway:

I like Perl best for scripts that are a few hundred lines or less.
I like Python for larger, more modular and extensible programs and 
software.

If someone had asked me to come up with a script to sort some files by 
their basename, I would reach for Perl in a heartbeat (and still 
wouldn't have had a script as elegant as Kevin's).

But at the point where I say to myself, "I really think that I could 
write this better and more easily if I used an object-oriented 
methodology and designed some class definitions to help me", I would 
turn to Python and not look back.



Erik







--
Erik Price

email: erikprice at mac.com
jabber: erikprice at jabber.org