Intro
As I mentioned in my review of Amazon’s Web Services Summit, Python seems to be the vogue scripting language these days. I decided I had better dust off the brain cells and try it out. I am an old Perl stalwart, but one senses that that language has sort of hit a wall after enthusiasm from 10 years ago began to wane. One of my example Perl scripts is provided in my post about turning HP SiteScope into SiteScope Classic. After deciding I needed a Python project only a few days passed before I came across what I thought would be a worthy challenge – simple yet non-trivial. That is the weekend puzzle as I understand it on NPR.
The Details
Start with a one-syllable, four-letter common boy’s name. Adjust all the letters with the ROT-13 cipher, and arrive at a common two-syllable girl’s name? What are the names? I’m pretty sure I could have figured out how to do this in Perl. Python? If it lived up to its hype then it should also be up to the task IMHO.
About the Weekend Puzzle
I listen to it most weekends. I often end up listening to it twice! I always think of whether it is suitable to be programmed or not. Most often I find it is not. I mean not suitable for the simple scripts and such that I write. I’m not talking about IBM’s Jeopardy-playing Watson! But this weekend I feel that the ROT-13 part of the challenge can definitely be aided by programming. Is that cheating? If I “give away” my solution as I am then I remove my unfair advantage in knowing a thing or two about programming!
The program – npr-test.py
#!/usr/bin/python # drJ test script - 4/2012 # to get input agruments... import sys #inputName = raw_input("Enter name to be translated: "); #print "Received input is : ", inputName # and see http://www.tutorialspoint.com/python/string_maketrans.htm from string import maketrans intab = "abcdefghijklmnopqrstuvwxyz" outtab = "nopqrstuvwxyzabcdefghijklm" trantab = maketrans(intab, outtab) inputName = sys.argv[1] print inputName,inputName.translate(trantab); |
So you see Python has this great maketrans built-in function that we’re able to use to implement the ROT-13 cipher. Of course veterans will probably know an even simpler way to accomplish this, perhaps with the pack/unpack functions which I also considered using.
You call the script like this:
$ npr-test.py john
john wbua |
I compiled a list of common four-letter names which I won’t fully divulge. They are in a file called names, one name per line. But how to quickly put it though this program? My old, bad lazy Unix habit was to do this:
$ cat names|while read line; do
npr-test.py $line >> /tmp/results
done
I’ve got it memorized so I lose no time except typing the characters. But I also know the modern way is xargs.
xargs is the really hard part
I keep thinking that xargs is a good habit and one I should get into. But it’s not so easy. It took me awhile to find the appropriate example. And then you run across the debate that holds that Gnu parallel is still the better tool. Anyhow, here’s the xargs way…
$ cat names|xargs -I {} npr-test.py {}|more
amit nzvg amos nzbf arno neab axel nkry ... |
Conclusion
This little python program speaks volumes about the versatility of this language. It does have some really interesting properties and at first blush is worth getting to know better. No wonder others have embraced it. It also has helped us solve the weekend puzzle!
The stated answer? Glen and Tyra. You’ll see you can feed either one of these names into the program and come out with the other. I found it amusing that Will Shortz described the puzzle as “hard.” I didn’t think so – not with this program – but I was not the randomly selected winner, either, so I didn’t get a chance to explain how I did it.
The guy who did win explained that he simply wrote the ROT-13 version of the alphabet below the alphabet so he had a convenient look-up table. Clever.