28 October 2013

If you have never ever programmed anything, you can find the title of this post strange. Are programmers somehow superhuman, capable of lifting railroad cars with their bare hands? Are they more intelligent, more capable than other people? Or is there a secret cabal of programmers where by joining you’ll get secret discounts at electronics stores and easier promotions at work?

Oh I just wish even just the second to last would be true, but alas, none of the above.

Being a programmer does not make you fitter (strangely often the opposite), nor stronger. But it does help quite a lot in many things. It’s also possible to do some really cool things if you mix in with some physical world stuff with the programming. However that’s not the kind of “making life easier” stuff I’m really talking about.

I was inspired to write this post because I’m trying to sell some stuff, mostly old magazines boxed up (why I have kept them in the first place, though?). There’s a nice free-to-advertise craigslist-style site used here in Finland that I’ve used before but. The but is there’s a length limit on the ad and I’ve got tons of those magazines to sell. Itemizing them goes over the length limit many times over.

So what do I do?

I whip up a Python script using Genshi formatting an YAML input file. The output is a bunch of text files, broken down by magazine names. Here it is, a total 9 lines of code:

#!/usr/bin/env python3
import genshi.template, yaml

data = yaml.load(open("data.yaml"))
tmpl = genshi.template.NewTextTemplate(open("template.txt"))
i = 1

for mags in data:
    names = list(map(lambda e: e['name'], mags))
    result = str(tmpl.generate(magazines=mags, names=names))
    print(result, file=open('out/' + (", ".join(names)) + '.txt', 'w'))
    i += 1

Time spent:

  • Script: 10 minutes
  • Writing text template: 5 minutes
  • Reformatting data to YAML: 30 minutes

Not bad — I did have the magazine data already available (text file, needing some reformatting for YAML) so this went quite nicely. After this effort I basically need just to log into the classified site and copy-paste the data file by file. (If I had really literally tons of ads to place I’d scripted the uploading part too, but I have just tens. Not worth optimizing that.)

Eventually I had to reformat the output several times before the site grokked it. I would hate even the potential of having to re-do something that tedious by hand, so I’m positive about the result.

There is great benefit in optimizing repeated tasks (xkcd has a nice illustration about it). Here I needed the script only once, so I’m not sure whether I came out ahead time-wise, but definitely I didn’t get to experience the tedium of doing so.

Come to think about it, the reason I did use templating was probably to avoid a tedious task by turning it into a programming problem. Writing a small script to do the task at least gave me a feeling of being productive even if it might not have been so.

Ha! Maybe that’s it:

Being able to write programs makes life easier by allowing you to turn (some) tedious tasks into interesting programming problems.

I’m happy with that.

P.S. So what about Excel? I do actually find spreadsheets quite useful as an miniature programming platforms when the data I’m manipulating is already in tabular form. Doing =if($B4<>"";TRUE;FALSE) and copy-pasting it over a row is often faster than writing and debugging an imperative program.

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