Thu Dec 3 21:25:43 MST 2009
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No warranties are implied or given in respect to the suitablity of this code
for any purpose, except maybe to consume disk space and bandwidth as you
download it.
You use it at your own risk. Do not abuse the code or your Karma will suffer.
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The following are my opinions, not anyone elses. Everyone else is entitled to
their own opinions, as wrong as they might be. :-)
I've been using Perl for years and years. I started using Ruby mid-2008. I
decided the other day that it's time to look at this Python thing, to see what
the differences are, and probably, in the process, screw up my brain forever.
Heh, what an odd thought. I never did drugs, instead I screwed my brain up by
cramming in too many programming languages and listening to Monty Python and
Firesign Theatre during my formative years.
So, when I first starting looking at Python, I was interested in figuring out
its similarities to Perl and Ruby, rather than what is different. It's kind of
that "glass is half full" mentality I've heard about but seldom practice.
Anyway, I like that, for the most part, Python is like a cross between Perl and
Ruby, just as Ruby is like a cross between Perl and Java. Talk about inbreeding
between the languages... but it works well for those of us who have to write
for the "internets" since these are the primary languages for the web and
interconnectivity.
I'm interested in hearing how to tweak and tighten the code, but not interested
in critiques of my programming ability or style - especially for the Python
code since I'm learning it as I go. The code presented here was written under
very tight, self-imposed, deadlines, typically less than a day for the initial
Python version, then less than a day for the Ruby and Perl versions. The code
is an example of what I'll write under the gun, but maybe not what I'd come up
with if I took more time to dig out non-standard libraries. If I need something
I do a quick search and if I see several recommendations for a particular
library and can grok it I'll go with it, otherwise I tend to go with whatever
comes bundled with the language.
After three days my impressions of Python are good. I don't like white-space
being significant, but the libraries seem to be pretty thorough. The docs don't
always make sense but I won't blame that on anyone - I think my dsylexia has
become worse over the last two years, probably from lack of sleep, and too much
stress. Swiping a phrase from Shakespeare, "To sleep: perchance to dream...".
Ruby's "POLS" attitde - "Principle of least surprise", seems to make the
libraries do more common-sense things by default. For example, Nokogiri is my
XML/HTML parser of choice, and it makes it really easy to surf through XML, RSS
and HTML docs. Compare the longer search commands required for Perl and
Python's parsers in the "rss" code for an example. I used Nokogiri for
production aggregator I wrote, and it was nicely handling malformed RSS that
other parsers croaked on, so I'm pretty happy and familiar with it. Perl's
XML::RSS threw errors and refused to work because it didn't like RSS with an
XML comment trailing the body. XML::RSS didn't turn on the recover flags for
libxml2, causing me to skip it entirely for another project, and go straight to
XML::LibXML. I think it's one of those "Ivory Tower" decisions made by the
developer to try to force the world to supply valid XML - a great idea, but one
that is doomed for failure in the reality of the internet.
OK, enough blather.
The codez:
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rss - This was to get an idea how I could navigate retrieved feeds using
Python. It's a simple feed reader that parses Guitar Center's used
equipment list which was open in my browser at the moment. It reads the
items and presents them in an HTML page, so the code could be used as the
basis for a CGI.
Here's some timing results for Python, Ruby, and Perl respectively...
Greg-MBP-wireless:rss greg$ for i in "python feed_item_titles.py" "ruby feed_item_titles.rb" "perl feed_item_titles.pl"; do time $i > /dev/null; done
real 0m0.696s <-- Python v2.6.4
user 0m0.115s
sys 0m0.063s
real 0m0.856s <-- ruby 1.8.7 (2009-06-12 patchlevel 174) [i686-darwin9.8.0]
user 0m0.301s
sys 0m0.088s
real 0m0.813s <-- This is perl, v5.10.1 built for darwin-thread-multi-2level
user 0m0.282s (ActiveState's version on MacOS 10.5)
sys 0m0.031s
get_docs - Code to retrieve the "Text Process in Python" files. Again, these
were in front of me when I came up with the idea.
craigslist_jobs - Code to retrieve current programming jobs that interest me
from my location (Phoenix-ish) with some keywords. Tweak the URL for
your location and the keywords to whatever you want. Outputs a standard
Content-type header and the RSS content so you can use them as a CGI.
gpherguson/comparisons
Perl, Python and Ruby comparison apps with similar functionality. Why? Because I can.
Python