Skip to main content

A brief reaction to "Find the Bug"

I picked up a copy of Adam Barr's Find the Bug, which is a cool concept for a book. (5 languages, 50 programs, 50 bugs; see if you can spot them.)

I found the bug in the first program, in C, then skipped to the Python chapter. The first two programs were not too bad, as pedagogical exercises go (although iterating through substrings instead of a.startswith(b) in the 2nd was painful). The third, though, was "Alphabetize words," 25 sloc to perform the equivalent of 

def alphabetize(buffer):
  L = buffer.split(' ')
  L.sort()
  return L

... doing everything about the hardest way possible.

Now, it's pretty hard to introduce a non-obvious bug into my version of this function, so it wouldn't be appropriate for Mr. Barr's book when written this way. But the right thing to do is to make the task more difficult, not dumb Python down to the level of C! It's very very painful to read Python written like that.

(Actually it's painful to read any language written at such a low level of expressivity, which is why I prefer not to use languages that really can't do any better.)

Comments

Agileotter said…
You mean like:
return sorted(text.split())
6:38 AM
Jonathan Ellis said…
Yes, except the book was written when python 2.2 was the latest, so sorted() wasn't available. And the book's code also just allows space as a word delimiter rather than any whitespace. I was trying to be fair, I guess to the point of pedantry. :)
8:53 AM
Anonymous said…
Hi,

I really like your website. I also have a blog about python, http://my-python-blog.freehostia.com/. It's about my adventures concerning my learning of python So anyway, I have a couple tutorial requests. Can you post a tutorial explaining how to make exe, dmg, bin/deb/rpm files? And can you create a tutorial about how to make a simple Jython game?
Thanks,
Yuval
10:18 AM
Tim Lesher said…
Q: What happens when you don't read a blog post carefully?
A: You spend five minutes staring at a three-line function, trying to figure out where the bug is.

Nice tip, though.... I'll have to add that book to my "to-read" list.
2:18 PM
Post a Comment

Popular posts from this blog

The Missing Piece in AI Coding: Automated Context Discovery

I recently switched tasks from writing the ColBERT Live! library and related benchmarking tools to authoring BM25 search for Cassandra . I was able to implement the former almost entirely with "coding in English" via Aider . That is: I gave the LLM tasks, in English, and it generated diffs for me that Aider applied to my source files. This made me easily 5x more productive vs writing code by hand, even with AI autocomplete like Copilot. It felt amazing! (Take a minute to check out this short thread on a real-life session with Aider , if you've never tried it.) Coming back to Cassandra, by contrast, felt like swimming through molasses. Doing everything by hand is tedious when you know that an LLM could do it faster if you could just structure the problem correctly for it. It felt like writing assembly without a compiler -- a useful skill in narrow situations, but mostly not a good use of human intelligence today. The key difference in these two sce...
Post a Comment
Read more

PyCon Python IDE review

I presented an IDE review at PyCon last Friday. It was basically a re-review of what I thought were the 3 most promising IDEs from the Utah Python User Group IDE review , to which I added SPE, which was by far the most popular of the ones we left out that time. The versions reviewed are: PyDev 1.0.2 SPE 0.8.2.a Komodo 3.5.2 Wing IDE 2.1 beta 1 I'd intended to base my presentation around a comparison of writing a smallish program in each of the IDEs, but the more I tried to make this not suck, the more I realized it was a losing proposition. Instead, I decided to try to focus on the features in each that most set them apart from the others (both positive and negative); this seemed more likely be useful. (I did a new feature matrix for this review, which is included after my comments. The slides I used are also up, at http://utahpython.org/jellis/pycon-ides.pdf , but aren't very useful absent video of the presentation itself. Hence this post.) PyDev PyDev has g...
43 comments
Read more

Why PHP sucks

(July 8 2005) Apparently I got linked by some PHP sites, and while there were a few well-reasoned comments here I mostly just got people who only knew PHP reacting like I told them their firstborn was ugly. These people tended to give variants on one or more themes: All environments have warts, so PHP is no worse than anything else in this respect I can work around PHP's problems, ergo they are not really problems You aren't experienced enough in PHP to judge it yet As to the first, it is true that PHP is not alone in having warts. However, the lack of qualitative difference does not mean that the quantitative difference is insignificant. Similarly, problems can be worked around, but languages/environments designed by people with more foresight and, to put it bluntly, clue, simply don't make the kind of really boneheaded architecture mistakes that you can't help but run into on a daily baisis in PHP. Finally, as I noted in my original introduction, with PHP, ...
30 comments
Read more