python vs perl lines of code

Larry Bates larry.bates at websafe.com
Sun May 21 00:43:52 CEST 2006


Edward Elliott wrote:
> This is just anecdotal, but I still find it interesting.  Take it for what
> it's worth.  I'm interested in hearing others' perspectives, just please
> don't turn this into a pissing contest.
> 
> I'm in the process of converting some old perl programs to python.  These
> programs use some network code and do a lot of list/dict data processing. 
> The old ones work fine but are a pain to extend.  After two conversions,
> the python versions are noticeably shorter.
> 
> The first program does some http retrieval, sort of a poor-man's wget with
> some extra features.  In fact it could be written as a bash script with
> wget, but the extra processing would make it very messy.  Here are the
> numbers on the two versions:
> 
>                Raw               -Blanks             -Comments
>            lines  chars       lines  chars         lines  chars
> mirror.py  167    4632        132    4597          118    4009
> mirror.pl  309    5836        211    5647          184    4790
>  
> I've listed line and character counts for three forms.  Raw is the source
> file as-is.  -Blanks is the source with blank lines removed, including
> lines with just a brace.  -Comments removes both blanks and comment lines. 
> I think -Blanks is the better measure because comments are a function of
> code complexity, but either works.
> 
> By the numbers, the python code appears roughly 60% as long by line and 80%
> as long by characters.  The chars percentage being (higher relative to line
> count) doesn't surprise me since things like list comprehensions and
> explicit module calling produce lengthy but readable lines.
> 
> I should point out this wasn't a straight line-for-line conversion, but the
> basic code structure is extremely similar.  I did make a number of
> improvements in the Python version with stricter arg checks and better
> error handling, plus added a couple minor new features.
> 
> The second program is an smtp outbound filtering proxy.  Same categories as
> before:
> 
>                     Raw             -Blanks           -Comments
>                 lines  chars     lines  chars       lines  chars
> smtp-proxy.py   261    7788      222     7749       205     6964
> smtp-proxy.pl   966    24110     660    23469       452    14869
> 
> The numbers here look much more impressive but it's not a fair comparison. 
> I wasn't happy with any of the cpan libraries for smtp sending at the time
> so I rolled my own.  That accounts for 150 raw lines of difference. Another
> 70 raw lines are logging functions that the python version does with the
> standard library.  The new version performs the same algorithms and data
> manipulations as the original.  I did do some major refactoring along the
> way, but it wasn't the sort that greatly reduces line count by eliminating
> redundancy; there is very little redundancy in either version.  In any
> case, these factors alone don't account for the entire difference, even if
> you take 220 raw lines directly off the latter columns.
> 
> The two versions were written about 5 years apart, all by me.  At the time
> of each, I had about 3 years experience in the given language and would
> classify my skill level in it as midway between intermediate and advanced. 
> IOW I'm very comfortable with the language and library reference docs (minus
> a few odd corners), but generally draw the line at mucking with interpreter
> internals like symbol tables.
> 
> I'd like to here from others what their experience converting between perl
> and python is (either direction).  I don't have the sense that either
> language is particularly better suited for my problem domain than the
> other, as they both handle network io and list/dict processing very well. 
> What are the differences like in other domains?  Do you attribute those
> differences to the language, the library, the programmer, or other
> factors?  What are the consistent differences across space and time, if
> any?  I'm interested in properties of the code itself, not performance.
> 
> And just what is the question to the ultimate answer to life, the universe,
> and everything anyway? ;)
> 
Sorry, I don't buy this.  I can write REALLY short programs that don't handle
exceptions, don't provide for logging for debugging purposes, don't allow
for future growth, etc.  I find that 60% of my code has nothing to do with
the actual algorithm or function I'm trying to accomplish.  It has more to
do with handling user's bad input, exceptions, recovering from hardware or
communications failures, etc.  Inexperienced programmers can write some
pretty short programs that get the job done, but can't handle the real world.

Also, many years ago I wrote a number of applications in APL.  We often
referred to programs written in APL as "write only code" because going back
to read what you had written after-the-fact was very hard.  You could write
in one line of APL what takes 1000's of lines of C or even Python and it was
pretty efficient also (for applications that needed to manipulate vectors or
matrices).

I understand what you are trying to say, but I can't support your conclusions
as presented.

-Larry Bates



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