80 chars per line is great

Probably the most controversial part of PEP 8 is the limit of 80 characters per line. Well, is actually 79 chars, but I’ll use 80 chars because is a round number and the way everybody referes to it.

Capture all the experience
Capture all the experience

There are a lot of companies where the standard seems to be “PEP8, except for the 80 chars line restriction”. On GitHub projects, which in general follow PEP8 (it seems to be a very strong consensus), that’s typically not found. In explicit code guidelines, the restriction could be increased (100, 120) or even removed at all. The usual reason for that is stating that we are not programming in VT100 terminals any more, and we have big, high-resolution screens. This is true, but I’ve found that that limitation, combined with the use of whitespace in Python, makes the code much more compact and readable.

It seems that, naturally, Python code tends to occupy around 35-60 characters (without indentation). Longer lines than that are much less frequent. Having suddenly a line much longer than the rest feels strange and somehow ugly. Also, having the mandatory indentation whitespace increase the line width is a good visual way of minimising the nested loops in your code and suggesting, in a subtle way, to refactor anything that is indented more than about four times.

For example, compare this:

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Great female participation on PyCon US 2013

This picture is AMAZING
This picture is AMAZING

I have read that around 20% of PyCon attendees were women. I’m sure I’ve seen it on more places I can’t find at the moment, but is at least here.

This is fantastic news, a great success for the PyCon, the Python community, and specially groups like PyLadies and Lady Coders. The opening statements of Jesse Nollan is a must see.

As I have previously expressed some concerns in this blog about whether requiring a Code of Conduct is the best approach, I’d like to say that I was wrong and it seems that had a positive impact. The CoC is also currently under review, and I’m sure it will be improved. It has also been used with great care, as the PyCon blog shows, which is also something to kudos.

There has also been special programming tracks for kids, which is awesome.

Of course, that is not the end of the road, and there is still much to do, but it is very encouraging. Keep on the good track!

Narcissistic numbers

Here is a nice mathematical exercise from Programming Praxis. Is about finding the “narcissistic numbers”, n digit numbers numbers where the sum of all the nth power of their digits is equal to the number.

To reduce the problem a little, I decided to start by limiting the number of digits. So, the first approach will be just calculate if a number is narcissistic of not. So, after checking it and making a couple of performance adjustments, the code is as follows…

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Thoughts on Code of Conducts

I’ve just read this statement from the PSF about requiring a Code of Conduct, and I felt somehow a little down.

Don’t get me wrong, I don’t think that a CoC is something bad, and everything it says (at least the referenced PyCon US one and the example in geekfeminism.com) makes sense. It’s just that needing a CoC feels a little … formal.

I don’t like very much formality, as I like to think that PyCon conferences are more a bunch of somehow friends getting together and sharing knowledge. I’ve always felt very welcomed in the Python community here in Ireland, and the atmosphere in PyCon IE (and other meetings) is absolutely fantastic. I haven’t seen anything that I will consider remotely discriminatory (like I saw back on my college years, for example). I’ve always imagined that the rest of the Python conferences and communities have the same “magic”.

Of course, I am seeing this from my particular, mainstream european-male point of view. I am a foreigner here in Ireland, but less say on “close, european orbit”. I’m not sure if some of the problems that the CoC tries to avoid are present and I am just not noticing. I’d like to think that’s not the case.

I don’t know, makes me think about what is the general perception and behaviour of the development community. I know there is discussion out there about wether the  geek population is welcoming to diversity or just a bunch of jerks that just can’t behave (and all the spectrum in between). I guess it just makes me sad to think that we may need “an adult” telling us not to say things that we already know that we shouldn’t. It’s 2012, we have no excuse.

As I say, I just feel a little… disappointed. Like thinking that there is something wrong in all that, that we are grow up and that things are not on the same level of friendly informality. That we need rules to ensure everyone feels safe. I guess that a small number of spoiled brats that can’t behave like adults and are just ruining the party to everyone else. :-(

In defense of resting

I have been watching recently some documentaries about software development, including the classic Triumph of the nerds (available in YouTube in three episodes, 1, 2 and 3) and Indie Game: The Movie. They are both very good  and I’d recommend them not only to developers, but to people interested in technology and/or entrepreneurship in general.

But they are very good exponents into something very present on the software scene, which is presenting crunch mode, working insane hours, in some sort of glamourised way. It is part of the usual storytelling and, and probably, part of the hard work -> ??? -> profit logic.

Let me told you something. When I was starting my career, on my first long term job, we once had a very strong deadline. This made us work in crunch mode for a long time (around 2 months). That meant working around 12 hours or more per day, 6-7 days a week. The very last day (a Sunday), I started working at 9:00 AM and went home the Monday at 6:00 PM, only stopping for eating something quick and going to the toilet. The rest of the team did similarly.

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ffind: a sane replacement for command line file search

Screen Shot 2013-03-26 at 22.53.13
I tend to use the UNIX command line A LOT. I find it very comfortable to work when I am developing and follow the “Unix as IDE” way. The command line is really rich, and you could probably learn a new different command or parameter each day and still be surprised every day for the rest of your life. But there are some things that sticks and gets done, probably not on the most efficient way.

In my case, is using the command `find` to search for files. 95% of the times I use it, is in this form:

find . -name '*some_text*'

Which means ‘find in this directory and all the subdirectories a file that contains some_text in its filename’

It’s not that bad, but I also use a lot ack, which I think is absolutely awesome. I think is a must know for anyone using Unix command line. It is a replacement for grep as a tool for searching code, and works the following way (again, in my 90% usage)

ack some_text

Which means ‘search in all the files that look like code under this directory and subdirectories that contains the text some_text (some_text can be a regex, but usually you can ignore that part)

So, after a couple of tests, I decided to make myself my own ack-inspired find replacement, and called it ffind. I’ve been using it for the last couple of days, and it integrates quite well on my workflow (maybe surprisingly, as I’ve done it with that in mind)

Basically it does this

ffind some_text

Which means ‘find in this directory and all the subdirectories a file that contains some_text in its filename’ (some_text can be a regex). It has also a couple of interesting characteristics like it will ignore hidden directories (starting with a dot), but not hidden files, it will skip directories that the user is not allowed to read due permissions  and the output will have by default the matching text in color.

The other use case is

ffind /dir some_text

Which means ‘find in the directory ‘/dir’ and all the subdirectories a file that contains some_text in its filename’

There are a couple more params, but they are there to deal with special cases.

It is done in Python, and it is available in GitHub. So, if any of this sounds interesting, go there and feel free to use it! Or change it! Or make suggestions!

ffind in Github
ffind in Github

UPDATE: ffind is now available in PyPI.

Magical thinking in Software Development

I guess we all Python developers heard this kind of argument from time to time:

Python is slower than C++/Java/C# because is not compiled.

Other than the usual “blame the others” when working with other companies (usually big corporations than thinks than using anything except C# or Java is laughable), you can also see a lot of comments in technical blogs or places like Hacker News or Reddit with similar, simplistic arguments. You can recognise them on the usual rants about how technology X is The Worst Thing That Ever Happened™ and Should Never Be Used™

That’s a form of Software Development Magical Thinking. This can be really harmful for software development, specially when the opposite, positive form is used. Let me define Software Development Magical Thinking in this context:

Software Development Magical Thinking noun Assuming that a technology will magically avoid a complex problem just by itself.

Probably that will become clearer after a couple of examples:

Java is a static type language and it is safer than dynamic type languages like Ruby.

We program in C++ so our code is very fast.

MongoDB / NodeJS / Riak is web-scale.

Please note that those are not completely, utterly wrong statements. C++ can be very fast. Static typed languages can avoid some bugs related with input parameters type. But there is no guarantee that creating a system in C++ is going to act like a magic wand against slow code. Or that Erlang will avoid having a single point of failure. And you’ll get as sick of bugs and security issues both on static type language and dynamic type languages. *

Those are all complex problems that need careful design and possibly measurements to deal with them. Deep analysis of the problem, which usually is more complicated that looks on the first place. Or even worst, the problem is not as bad as it looked and the designed system is more complex that it should, trying to catch a problem that never arises. Not to exclude having previous experience to avoid subtle errors.

Let me say it again. There are problems that are HARD. In software systems they are confronted almost daily. And no single thing will make you forget them. Even if you use a very good tool for what you’re doing (like Erlang for concurrency), which usually implies paying a price (in development time, etc), doesn’t replace vigilance and issues could eventually appear. Unfortunately, making software is tough.

The problem with Software Development Magical Thinking is that it is very easy and it is also very natural. Seductive. We know that “general Magical Thinking”, simple solutions to very complex problems, is quite common. Hey, a lot of times, it even seems to work, because the Feared Problem will only present after certain size that is never attained, or after the designer leave the company and left a latent problem behind. Most of the time, making a totally informed decision is unrealistic, or simply not possible, and some risks must be taken.

But as software developers we should know that things are not that easy, even if we have to compromise. Each bug that takes time methodically eliminating causes. Every measurement that makes you wonder what is the best metric to reflect a value. Every time you realise that there was a back-of-the-envelope calculation that shows something that will have an impact on some design aspects. Those are all reminders that should makes us think that there are no silver bullets and we shouldn’t take lightly all those difficult problems.

Make decisions. Design systems. Choose a tool over others. Take risks. But don’t be delusional and careless. Be conscious that software can bite you back. Be vigilant. Be skeptic. Avoid Magical Thinking.

PD: And please, don’t say “Python is slow”. Just don’t. It is not for most of the jobs. It is not going to make you win a discussion unless you carefully measure and proof it. And, perhaps most importantly, raises my urge to kill.

* No, I am not going to comment anything the Mythical Web Scale property.

EDIT: Wow, it has been submitted to Hacker News here. Just in case any one whats to add to the discussion there.