Code Kata: Becoming a better developer

http://codekata.pragprog.com/2007/01/code_kata_backg.html

by ColinWright • 15 years ago

116 30 15 years ago

codekata.pragprog.com

koopajah• 15 years ago

These are nice exercises. That could help me motivate myself to start learning a new language and improve a bit like project-euler did for a bit!

roel_v10• 15 years ago

The problem with this is the same problem that shows in actual karate kata in the context of its broader supposed relation to actual fighting: people get caught up in the minutiae of the exercise itself and forget its purpose, which is to win a fight (or, write a full-on application that does what users want it to do).

In karate, this has caused the dilution of most forms of karate (with the exception of Kyokushin) into little more than ritualized movements, where the vast majority of even high-level teachers don't know how it relates to a real fight. Pure theory has taken over - 'when your attacker does a simple forward kick ('teep', don't know what it's called in English), move the leg with your hand!'. Except that that never happens in the real world, and yet it's a core movement in many kata (and kihon etc, not just kata).

Now, how does that relate to software? Just knowing how to write a binary tree, or linked list, or singleton, or whatever, doesn't make one capable of writing a program that users want to use. Yes, maybe it makes one capable of writing a perfect program even, in the sense that it may even be mathematically proven correct; yet that's absolutely irrelevant outside of the realm of the theoretical. The basics of this nature are well-documented everywhere already, and it's not necessary to know all of them before doing more integrated exercises; full applications that people actually want to use.

Or to make the connection back to martial 'arts' (I hate that word, what's 'arty' about it? We need to get rid of the mystical aura around it - it's fighting, a methodology to inflict maximum, concentrated or controlled damage onto another person, sorry for tangent - it's a pet peeve ;) ); we need to get rid of the karate's, tae kwon do's and capoeira's of the software world (disclaimer: I have brown belts in judo and karate, I get to have an opinion on it ;) ) and we need to go back to the essence - the mixed martial arts of software development: the misv or startup or whatever you want to call it. Actual products for actual users, not fetishising technology for technology's sake.

(second disclaimer: I know I'm sort of arguing a straw man here, nobody said anything about not making end-user products, but it's a lot easier to make a point when you don't have to put in all the nuances ;) )

route66• 15 years ago

No.

I would consider it helpful if there were more people in the industry who would know what a binary tree (or whatever comes to mind) is and when to use it. all means to get there are welcome as far as I'm concerned.

This l'art pour l'art accusation comes back once in a while, often in language bashing ("elitist lispers" I read some days ago). As a former musician I recognize it in the shape of "technique ruins your soul" or how one would like to phrase it.

I think that the dichotomy is just wrong. It's not detailed knowledge versus pragmatic solution. I spent a great amount of my time in environments where the "shipping it" dominated "understand what you are doing", and I also spent time with drummers who could not keep the time because practicing would ruin their soul. It's knowledge vs. ignorance.

What concerns software development: the essence you want to get back to smells to me like the vbscript world I was happy to turn my back to. I would like to see more capoeira, less hash-tables because they are built in.

To follow up on your analogy with martial arts: I practice fencing once in a while, a rather ritualized sport, (for some 100 years already): I would not like to inflict maximum controlled damage to my opponent, or the other way round: I'm not training to kill. You might call it a kata I'm working on.

Your point "it's not necessary to know all of them before..." I cannot argue with. I would think the same. But the inequality "written by a programmer who cares about knowing his craft" != "people don't want to use" follows not from that statement nor from any other point you are giving.

singular• 15 years ago

Indeed - I personally think that half the problem with a lot of the software I've worked with is people getting addicted to the idea of just making stuff work and judging quality against that. Any mysterious problems with maintainability / performance / the groans of your colleagues are just strange outside problems that have nothing to do with you and can't be helped and they really should shut up with their new-fangled silly ideas - my stuff works and surely that's what matters?

A typical quote from these people might be 'the user doesn't care about the implementation details' - that's true, in the same way a car owner doesn't care if the car's engine is made out of cheese.

Somewhat understandably people start to form an ego around this idea, making it harder and harder for them to assess whether there might be better means of engineering their software.

As with much of software engineering, the problem is with the wetware rather than the (soft|hard)ware :)

rimantas• 15 years ago

You may have your opinion, but having it does not make it right.

Ir your teacher does not know how kata applies to real fight — that's just too bad.

roel_v10• 15 years ago

I've trained with dozens over the span of almost 20 years, and none of them could even hold their own (let alone win) a fight against even moderately skilled fighters in modern fighting styles. Of course, every single one of them would have lots of theories on how the various kata / poomse / whatever could/would apply in a real fight, but most of the explanation I heard were ok-ish in theory but had been definitively disproved in practice for years.

Even I, having had only rudimentary training in more 'goal-oriented' fighting styles, fairly easily dominate practitioners of more 'classic' styles (not because I'm good, but because of the ritualisation and artificial limiting to make things 'more pure'). I catch every judo player (once it goes to the ground, which is not hard to do with them with a single leg takedown since they don't know it...) in either a guillotine or straight leg lock. I mean, come on - that's groundfighting 101 right there.

(it's a bit unfortunate that I use judo here to illustrate, since they much less pretend to be a 'martial art' and refer to themselves much more as a sport than others do, it's just the example that was the first that came up to me).

And it's true that opinions don't make anyone right, but I consider it generally accepted and broadly empirically proven that practitioners of 'traditional' martial arts stand no chance against more goal-oriented and broadly skilled fighters. I'm not going to go into a 'my teacher could kill anyone with his death pinch if he wanted' argument here (bullshido.com forums style 'discussions' get old very soon).

kelly5• 15 years ago

I agree that you need more than mastery of the movements to win a fight, but the reason exercises like kata are so valuable is that when you master the movements your mind is free to focus on higher level problems.

When I studied Mathematics in elementary school I didn't memorize all of the multiplication tables because I thought I could always use a calculator if I wanted to multiply. Years later, when learning Algebra I had to go back and memorize those tables because having to calculate simple products and quotients was slowing me down. Knowing multiplication tables isn't necessary or sufficient for being able to do Algebra well, but it sure speeds you up.

I often practice my coding skill by doing problems like the algorithm problems on TopCoder. I find focusing on coding and solving problems quickly improves my work productivity in a way that doesn't come just from doing that work alone. I think these Kata will be even more useful for building the low level skills I use often in my work, so thanks to the original poster!

rajivrnair• 15 years ago

"Thats my linked list son"

http://zedshaw.com/essays/master_and_expert.html

impendia2• 15 years ago

> In karate, this has caused the dilution of most forms of karate (with the exception of Kyokushin) into little more than ritualized movements, where the vast majority of even high-level teachers don't know how it relates to a real fight.

Sorry, as a black belt in karate, I am not going to let this stand.

Would I be able to handle myself in a fight? Maybe not. I really liked the stylistic, artistic side. But my teachers, who mastered both the stylistic and the practical, sure as hell knew what they were doing. In the first place, they had honed their punching and kicking skills to the point where they would be able to execute them perfectly in a fight.

But we practiced all sorts of moves, many of them grappling on the mat, that derived from the kata. For example, the Naihanchi ("iron horse") kata is done standing up, but really relates to ground fighting. Most of my teachers were extremely competent either standing up or on the floor, and we did lots of partner drills which got as close to a fight as could be done without injury, and which were heavily informed by the kata. A lot of times the connection was subtle.

I'm sorry that you got brown belts and were disappointed in your training. There are teachers that suck and teach total BS. Also, karate may not be the best thing to learn if you simply want to handle yourself in a streetfight.

But "little more than ritualized movements"? Have some respect.

roel_v10• 15 years ago

Note that I said 'relates to a real fight', and in that place did not say 'handle in a real fight'. I agree that a trained karateka will have a significant advantage against an untrained opponent in any sort of fight.

That said, I disagree with the rest of your point. Naihanchi does not in any shape or form prepare one for any sort of fighting, be it on the ground or standing up. Of course when one does kumite 3 times a week, that does train one as a fighter, even if not maximally efficient; but it's far-fetched to say that because the movements of limbs in kumite sort of resemble the movements of limbs in a kata, that the kata adds significantly to the training for kumite-style competition (or 'actual' fighting, for that matter).

I also did not say that I was disappointed in my training. I got a lot out of it actually, and if I had more time I would still be training; but I no longer pretend that I learned effective fighting from it. I see it more as a fast paced yoga, and fun mix of medium-intensity cardio training and flexibility exercises. Which is fine. Also without actually doing it, I wouldn't have been able to draw the conclusions about its place in martial arts that I do now.

Finally, I'm not saying that the theoretical parts can't be fun, just like in the software cases that we started with. I have spend numerous hours toying with non-practical examples or test programs, for aesthetics or a minute performance enhancement or whatever. Similar in karate - I spend many hours in front of a mirror getting my side kicks perfectly level, for merely aesthetic reasons. Many people do - which is why I said the things I said, that the original goal has largely been forgotten. I mean seriously, kata competitions are seen as the 'noble' form of competitive karate, and kumite is just for youngsters with too much testosterone and roughnecks; does that make sense?

bphogan• 15 years ago

Your experiences with the martial arts don't coincide with mine at all. To this day I still practice my kata. Like with my code, I may never achieve perfection, but I will never be satisfied with my current level. I used to hate the kata, but then it started to make sense.

Kata, and code kata, is about practicing. So you're ready for battle. You shouldn't be practicing when you're fighting, and you shouldn't be practicing when you are getting paid to deliver a product.

This is true in anything. There are tons of "guitar" players who would rather play by ear, learn a few chords, and start a band. Then there are those musicians that spend the time to learn the boring fundamentals. And they practice those fundamentals over. And when you hear them play, you'll know they are masters. I think that holds true for coding too.

Kata teaches discipline and patience. It's like learning to breath. Practicing the basics in excruciating detail over and over again ensures you don't freeze up under pressure.

sunsu• 15 years ago

The Japanese word you are looking for is "Bunkai" ("Bunhae" in Korean Tae Kwon Do). Contrary to what you say, many masters still teach it when teaching "Kata" or "Hyeong". If you are taking a style of Karate or Tae Kwon Do where it is not taught, you should probably find a new instructor.

roel_v10• 15 years ago

Yes, of course, but bunkai are not standardized and oftentimes quite ridiculous - with multiple attackers, and jump kicks and outrageous simultaneous blocks/attacks. I've done many public demonstrations which were mostly show performances, like in a Bruce Lee movie; but they don't resemble an actual fight in any way. I'm not sure if you're arguing that kata resemble a real fight, because that's even a step further than other posters are doing, but even assuming that you're just arguing that bunkai help one to visualize the potential circumstances the movements in kata can be used in, they're so stylized as to be completely irrelevant in real life.

I mean, all of you must have had karate teachers that would let you walk from one side of the gym to the other, doing straight punches, and taking take or proper foot placement, hip movement, fist height and position, etc? While the teacher walks around and corrects posture and style? All those hours you've done that (and I have, too) are completely useless from a 'learning to fight' point of view. They are needed to become a good karateka, yes, but none of it will help you throw a useful, as opposed to beautiful, punch.

dmbass• 15 years ago

About your pet peeve, "art" has more than one definition, so you may want to rethink being annoyed by calling a style of fighting a "martial art." See: http://www.merriam-webster.com/dictionary/art?show=1

roel_v10• 15 years ago

The common usage of 'art' is a lot more nuanced that what you are trying to make believe with a clinical definition.

"skill acquired by experience, study, or observation" - does that mean that when I learn to butcher a pig by watching youtube videos of it, it becomes an art? Of course not. "art" implies some form of subjective addition to it, usually for a "higher purpose", not just functional (I'm not trying to come up with a definition of "art", as whole libraries have been written about it, I'm just stating that you implying that anything that is learned in some form is an "art" does not correspond to the common usage of the word).

grannyg00se• 15 years ago

Regarding your pet peeve, don't you think that the individual's style, interpretation, and individual application of taught material make it a form of art? You similarly teach painting technique and skill, and repetitively practice a certain technique, even on the same image over and over again. Once the person learns what you are attempting to teach, and they start to implement it in their own way, in new scenarios, then it starts to become artful.

roel_v10• 15 years ago

I didn't mean to let this go off into a discussion on when something is 'art', but by this definition playing soccer is an 'art' too. When one leaves the notion that fighting is the goal, then I guess it can become an 'art'; but that's not what people mean when they say 'martial art'. They like to still have it be associated with effective fighting, yet at the same time also have it float in a cloud of mysticism.

What I'm saying is - either some style is a dance or stylized movement form, or it's a system to fight effectively. The first I don't mind calling 'art', frankly I don't care much about it. The second is not 'art', it's science - it's about finding (through hypotheses, falsifying them, empirical testing, the whole yadda yadda) the most effective way to inflict various forms of damage to a human body (one can debate how far the use of tools can go in this - if swords are OK, why not landmines; but that's a different discussion).

mcantor• 15 years ago

Internalizing the correct ritualized movements lets you forget about them so you can focus on high-level strategy (winning fights/writing applications).

Lego bricks are hard and consistent and unchanging, and you need them to build incredible novelties.

BTW, my personal belief is that they are called "martial arts" because "art" is simply creating novelty within a system of constraints. Also, you are incorrect that all martial arts are concerned with inflicting damage--there are many arts and corresponding practitioners who encourage and value the mystical aura, because martial arts can be used as a vehicle for personal growth, discipline and spiritual nourishment. Please be careful about generalizing your experiences!

stiff• 15 years ago

Just knowing how to write a binary tree, or linked list, or singleton, or whatever, doesn't make one capable of writing a program that users want to use. Yes, maybe it makes one capable of writing a perfect program even, in the sense that it may even be mathematically proven correct; yet that's absolutely irrelevant outside of the realm of the theoretical. The basics of this nature are well-documented everywhere already, and it's not necessary to know all of them before doing more integrated exercises; full applications that people actually want to use.

You state that theory is diverged from practice, which in general is one of the most rotten notions people commonly hold, but the very same sentence seems to indicate that you don't really understand the theory you're talking about - you first equate Computer Science to mathematical proofs of correctness, then you imply that proofs of correctness are useless in practice, both statements being equally unwise. Your users still want to use fast software, solve hard problems, do not like to find bugs in your programs and your colleagues still would prefer that the code you are writing is easy to understand and easy to maintain. It is not possible to go long-term about solving hard problems (writing fast programs being one of them) without knowing or inventing the necessary theory, and without lots of experimenting as well, for which there is ample historical evidence in the history of science and engineering.

I don't care if you do book exercises, katas from the web, or invent your own toy project, but you have to practice writing programs, including small programs, involving some actual domain problems (theory!) to be a really good programmer. A few times when doing recruitment for my company I asked the candidates to prepare a small program for me, first time a program extracting links from a given url, the other time a small TCP chat server and client. Such a program can be elegantly written in a page or two of code, yet 90% of people can not write a bug-free program of this kind at all, not to mention achieving elegance (ease of understanding the code + good maintainability + good performance). They of course won't cope well with a larger program and/or larger problem, they are just used to patch things together in a chaotic way until they find a combination that works. This tactic doesn't scale well to hard problems unfortunately.

The only reasonable function of the analogy to Karate is that calling an exercise a "Kata" might be motivating for some people and sounds nice. Carrying it any further doesn't have any meaning. For one, 90% of the time you spend doing Karate is doing various kind of exercises and you get in a "real fight" a few times in a lifetime perhaps. No wonder martial arts that spend those 90% of the time on something more related to the situation you want to be prepared for actually get you better prepared for the situation. I also doubt the goal of Karate is beating people up in the street or in some fancy cage. In programming the exercises are just an addition to performing your real work, which is probably done almost every day anyway.

roel_v10• 15 years ago

You need to practice more in making your ad hominems more subtle and try to provide at least some actual reasoning for the things you claim, and if you're going to call people stupid you can at least try to do so by referring to things they actually said.

Anyway, what your users want is a program that they can figure out how to use, and one that they actually can get on their computer, and that does the things they need them for - all of which have absolutely nothing to do with whether you used a quick sort or a bubble sort. Being fast, solving "hard problems" (methinks you're a bit full of yourself - when was the last time you heard someone say 'man, if only I had software that would solve a hard problem'?), and being maintainable are all secondary to the actual use - i.e. having a user interface they can understand, provide output in terms they understand, etc.

In your second paragraph you are actually making my point for me, but you don't seem to realize. What users want is a program that does something for them, like extracting links - and they don't care if those links are stored in a linked list or array. Maybe in some cases they will care at some point in the future that, when they download 10's of thousands of links, that happens a few seconds faster in some cases than in others, but that's not their main concern.

danso• 15 years ago

KataFour, regarding data munging, makes me smile...I've had to do this so many times while wondering, "Is this hard just because I'm doing it the wrong way?"...but it's good to see it's worth a brainteaser exercise.

The weather.dat file in particular is like a vexing issue I've come across when converting PDF tables to text and then writing a script to delimit them. You can't just use a regex because some rows are entirely blank for some fields.

I wrote a solution here for PDFs I had to munge for work: http://www.propublica.org/nerds/item/turning-pdfs-to-text-do...

Basically, you start with some regex pattern as a delimiter and loop through every line and record the left-most position of each value. Then you compare it to a global array that stores the left-most position so far found in the document for a particular column. If the current row has a column x that starts farther to the left than the global array's column x, then that must mean there is a column between x and x-1.

There's some tinkering that has to be done with that, especially if the PDF to text conversion was ugly. But it would work pretty well for this particular set of data.

Code Kata: Becoming a better developer

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