Mailman 3 March 2005 - Edu-sig

RE: [Edu-sig] Re: Best approach to teaching OOP and graphics
by urnerk＠qwest.net 25 Mar '05

25 Mar '05

Original Message: ----------------- From: Dan Crosta dcrosta(a)sccs.swarthmore.edu Date: Fri, 25 Mar 2005 11:52:37 -0500 (EST) To: edu-sig(a)python.org Subject: [Edu-sig] Re: Best approach to teaching OOP and graphics Linda Grandell wrote: > > > In my book, OOP and graphical programming *are* two different things. >> I totally agree on this. What I, however, do see as a potential risk >> here is that the division might lead to students thinking thoughts such >> as >First of all, I disagree here. Well -- they are. But they really shouldn't >be. Although we sound like a disagreeable bunch perhaps, I think we're all in general agreement. Graphics programming is very OOPish in most implementations and it makes a whole lot of sense to do graphical programming (GUIs, games, whatever) using objects. The typical think is to export an API in the form of objects with methods and properties. This is how every Pythonic graphics library I'm aware of works. You import a module and you get access to a lot of GUI widgets in the form of objects with methods. You can subclass these widgets or compose them, the way OOPers always do. Typically, we instantiate a window or frame object (some canvas deal) and populate it with buttons, pull-downs and whatever it is. Typically, clicking or mousing over results in events, which our code traps, often by means of callbacks, but maybe by means of the observable/observer design pattern (like Java's). Typically the events themselves are objects (e.g. mouse over events). I just saw a demo of using Python on the Nokia 60-series (a cell phone model). Same thing: a little phone-specific API is imported and appears to the programmer as objects. >Python). Once we got into the real meat of the assignments, we had a much >easier time when we only had to reimplement a few functions, thanks to >inheritance, rather than rewriting whole functions from the ground up. Absolutely. I bet we all agree. >To finish, I'd say that you should consider what you want the students to >get out of the course: if you just want them to have a good time, then >programming some procedural stuff with graphics (say, a tron-like game, >which I did in Java/AWT/Swing when I was in high school) might be a good >idea. If you want them to really learn about object orientation, I think >working in an object-oriented modeling system, even if you just end up >doing simple 2D stuff, makes a whole lot more sense to me. > >dsc I'm a little confused why you'd bring up Java/AWT/Swing as your example of doing some procedural stuff with graphics, as this language is highly object oriented in the way you described previously. But here's the thing, the question I think we're asking in this thread: how do we make it clear to students that OOP is NOT *just* about graphical programming? You can write highly object oriented code that has no GUI whatsoever, is invoked only from the command line with switches, maybe runs in the background as a daemon process (like a database) and communicates with the outer world only through some ports over TCP/IP. Is there anything less OOP about such code, which has no graphical shell? No. OOP, as a concept, is conceptually distinguishable from doing GUI or game or graphical programming, even though, as a paradigm, it has become probably the most popular way of doing all of those things. Kirby Other fun things at Pycon 2005: Python used to write a prototype Air Traffic Control system (prototype only in the sense that it's not commercial yet -- not in the sense that the "real" version would be written in something else (it'd stay Python)). Python used in a language teaching engine with Unreal Tournament 2003 as the simulator (showing fictional Iraqi town) and a speech recognizer. Soldiers train on this before going to Iraq. The mission is basically one of "take me to your leader" except it's more "Hi, I'm Joe, this is my team, where's your main guy and could you please give me directions" (all in Arabic, with the detailed directions likewise in Arabic). I did a presentation on Hypertoons that generated some interest. -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ .

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Re: Best approach to teaching OOP and graphics
by Dan Crosta 25 Mar '05

25 Mar '05

Linda Grandell wrote: > > In my book, OOP and graphical programming *are* two different things. > I totally agree on this. What I, however, do see as a potential risk > here is that the division might lead to students thinking thoughts such > as First of all, I disagree here. Well -- they are. But they really shouldn't be. In my opinion (speaking as a Computer Graphics undergrad), computer graphics are a fundamentally object-oriented task. You're manipulating meshes, polygons, lines or points inside one or more graphical contexts, and each of which share certain attributes (location, color) and methods (translate, draw). This suggests a strong class heirarchy to me, and in fact, when I went about writing my own graphics library last semester, my partner and I took a heavily object-oriented approach (though in C++, not Python). Once we got into the real meat of the assignments, we had a much easier time when we only had to reimplement a few functions, thanks to inheritance, rather than rewriting whole functions from the ground up. Additionally, I think graphics provides a helpful visual metaphor for heirarchical systems, which is, in my opinion, an important part of understanding object orientation. If you have a model heirarchy like: - Model m - SubModel a - SubModel b And you call m.translate(10, 0, 0), the students will see that a and b translate by 10 in x as well. This is metaphorically analagous to changing the impelentation of a method or value of a field in a base class, and having that change reflected in the children. In fact, non-OO graphics systems (I'm thinking OpenGL) basically are object oriented, just without the benefit of living in an OO language. You find, when programming OpenGL, that you do a lot of PushMatrix() and PopMatrix(), which implicitly defines 'objects' in the sense of bits of graphical stuff that move around together. Other begin and end calls work similarly. To finish, I'd say that you should consider what you want the students to get out of the course: if you just want them to have a good time, then programming some procedural stuff with graphics (say, a tron-like game, which I did in Java/AWT/Swing when I was in high school) might be a good idea. If you want them to really learn about object orientation, I think working in an object-oriented modeling system, even if you just end up doing simple 2D stuff, makes a whole lot more sense to me. dsc

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reappearance of old postings
by Gregor Lingl 25 Mar '05

25 Mar '05

Hi, there just appeared a couple of postings from a Jan 2004 thread (on primes) on this list again. (two of them by me) To me it's completely unclear why and how this could happen. Does anybody know ...? Gregor -- Gregor Lingl Reisnerstrasse 3/19 A-1030 Wien Telefon: +43 1 713 33 98 Mobil: +43 664 140 35 27 Website: python4kids.net

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Re: [Tutor] what? (late nite entertainment) (*)
by Gregor Lingl 24 Mar '05

24 Mar '05

Now: early morning corrections ... Alfred Milgrom wrote: > Hi Gregor: > > Hard to work out what is what :) as there seems to be a typo in one > line of your code: > > if x[z]: x[z*z:n:z]=y[z*z:n:z] > > (At least it doesn't work on my machine with Python 2.2) > Yeah, I had the idea when playing around with some new features of Python 2.3, as I do sometimes late at night - before shutting down my computer. This one I found at: http://www.python.org/doc/2.3.3/whatsnew/section-slices.html and I looked for an example for use of "assignment with extended slices" ... > Also the subroutine breaks for n = 1 or less. > Maybe you need a line at the start to say > if n <2 : return [0] > what() was intended to generate all primes less than n. (In fact it's an implementation of the sieve of Eratosthenes). The bugs came not only from not beeing interested in primes less than 2 ;-) but also from beeing a little tired already. Sorry. I think the following version repairs that - and hopefully uses less obfuscating variable names (which in fact originally was part of the "riddle"): def primes(n): sieve, zeros = range(n), [0]*n sieve[:2]= 0,0 i = 1 while i*i < n: if sieve[i]: sieve[i*i:n:i]=zeros[i*i:n:i] i += 1 return [p for p in sieve if p] Regards, Gregor >

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Best approach to teaching OOP and graphics
by Linda Grandell 23 Mar '05

23 Mar '05

Dear all, During the last six months, I have given an introductory programming course to high school students using Python. The course covered the fundaments of programming: data types, conditionals, loops, files, exceptions, modules, functions, and so on (no graphics). At the same time I taught Java to another group of high school students, which turned out to be a really "eye-opening" experience; using both languages at the same time really pointed out the advantages of Python. Starting in mid-April, I will give a continuation course to the same students now including OOP concepts and graphics. Based on my positive experience of Python, I will continue using it as the language of instruction. In addition, I am curious about trying out pair-programming in high school settings, and have therefore decided to use this methodology in the course. So far I have come up with two alternatives for how to go about this course: 1) Use PyGame from the very beginning of the course. 2) Cover OOP in the traditional (text-based) manner, using IDLE as in the basic course, and later in the course introduce a GUI module, e.g. AnyGUI, for graphical programming. Using the first approach, graphics could be introduced already during the first lecture, and no distinction would have to be made between non-graphical and graphical programming. This might, on the other hand not be the case with the second approach; in fact, I feel there may be a risk of the students developing an idea of OOP and graphical programming being two different things if they are introduced separately. As an active lurker on the edu-sig list, I therefore decided to present my small "dilemma" here. How do you think OOP and graphics could best be introduced in high schools? Is one of my alternatives OK, or do you have other suggestions? The fact that the students will be working in pairs will hardly affect the choice of teaching approach. Best Python-regards, Linda Grandell Åbo Akademi University Turku, Finland

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9. Best approach to teaching OOP and graphics
by Darren Payne 23 Mar '05

23 Mar '05

> 9. Best approach to teaching OOP and graphics > (Linda Grandell) I too taught Java and Python to 2 separate classes 2 years ago. Funny, the more Java I taught the less I liked it ... but then you get over it and just put up with Java's ways, plus loads of ppl have coded modules to get around many of the short comings. I still feel very negative about Java - it's so much hype and hot air really. Pair programming is fine and works best when both are of equal ability. I would encourage you to avoid putting a stronger / more able person with a weaker / less able person - the stronger one will get very little out of it and can become quite resentful. I really cannot comment re GUI. ----------------------------------------------------------------------------------- regards Darren Payne Hurlstone Agricultural High School Ph: 9829 9222 Fax: 98292026 Find local movie times and trailers on Yahoo! Movies. http://au.movies.yahoo.com

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Re: [Edu-sig] Best approach to teaching OOP and graphics
by Linda Grandell 23 Mar '05

23 Mar '05

> In my book, OOP and graphical programming *are* two different things. I totally agree on this. What I, however, do see as a potential risk here is that the division might lead to students thinking thoughts such as "So now we quit the OOP part and continue with graphics. OK, so no we don't have to worry about those things anymore" Although thoughts like these would be rare, I still feel I need to consider them when deciding on what approach to take in the course. In my experience, stronger students have no problem in seeing the orthogonality of things introduced, whereas the weaker students might find it difficult to even understand that one can use the fundamental structures just about anywhere (e.g. nesting for-loops), as long as the logic holds and the syntax rules are followed. Students like these might get ideas as the one above. Anyway, whatever approach I choose, I am planning on starting with a brief repetition of the basics before rather quickly moving on to OOP. In my opinion, the way you Kirby go about objects is just about perfect, and I am planning on following the same idea. If we were to use the pygsear module together with PyGame, we could go graphical from the very first class. If we, on the other hand, were to use e.g. Zelle's graphics.py (thanks for reminding me about that one, had somehow managed to forget it) I would probably introduce OOP first and then continue with graphics. But then again, there is nothing stopping me from introducing the graphics in the middle of OOP either... Gosh, I just realized that I have a lot of pondering to do over the Easter holiday :) /Linda

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Undergraduation
by ajsiegel＠optonline.net 22 Mar '05

22 Mar '05

Paul Graham's recent essay addressed to college CS students: http://www.paulgraham.com/college.html has a discussion of where he sees math fitting in. saying, on one hand, that math is *not* a core skill for a hacker and on the other: """ It's a valuable source of metaphors for almost any kind of work """ and therefore """ One of the most valuable things you could do in college would be to learn what math is really about. This may not be easy, because a lot of good mathematicians are bad teachers. And while there are many popular books on math, few seem good. The best I can think of are W. W. Sawyer's. And of course Euclid. """ I think I could add a number of works of math literature to that list. What isn't addressed is the intersection of math and hacking, in the other direction: i.e. the usefulness of the some skills of a hacker for someone who takes the advice to "learn what math is really about" as a "most valuable thing" - and the more general and primary goal. I found it a good enough reason to learn to hack, a bit. And it nice to see that Graham seems to understand why that might be true. Art

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Re: RE: RE: [Edu-sig] RE: Concentric hierarchy / hypertoon (was pygame etc.)
by ajsiegel＠optonline.net 20 Mar '05

20 Mar '05

----- Original Message ----- From: Kirby Urner <urnerk(a)qwest.net> > > > The problem though, in my view, is that it is on fourms like > > edu-sig ( and debian edu list) that the exploration of these kinds > > of "polemics" are both most relevant and least welcome. > > > > Which says something in-and-of-itself. > > > > Let's just put it this way: I'm a technologist immersed in IT and > I don't > consider myself a formidable obstacle to progress. Nor do I feel > that my > innovative programming is encountering any effective resistance. > Nor do I > feel that I'm operating alone or in a vacuum. > > On top of this, I see a million ways to link up design science > (Fuller'sname for a disciplined approach to making headway) with > open source > projects. Of these million ways, I've so far exploited only about > 4.5% of > them (bogus stat). In other words, I'm loaded with "ammo" > (weapons of mass > instruction) but have only lightly tapped what's in inventory. I am also a technologist of a fashion. But in the business world there are factors that converge toward appropriate use. There is cost and there is benefit, and there is a measuring scale - dollars. I find the business world quite wholesome in that respect. What I see at work in the realm of education and technology is the worst of both worlds - folks working within self-interested frameworks of various kinds and degrees (as in the business world), but without a reasonable framework for defintions of goals, or measurement of costs and benefits, and therefore no ecosystem that it is reasonable to believe will converge us toward a reasonable result. The easiest shortcut, of course, being to simply define "educated" - because there is in fact a lot of leeway to be had in coming to a definition of that word - as fluent in working with computers. In which case - by simple tautology - working with computers becomes a centerpiece of the educational process. Too easy, IMO. Way. Art

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Re: RE: [Edu-sig] RE: Concentric hierarchy / hypertoon (was pygame etc.)
by ajsiegel＠optonline.net 20 Mar '05

20 Mar '05

----- Original Message ----- From: Kirby Urner <urnerk(a)qwest.net> Date: Sunday, March 20, 2005 11:19 am Subject: RE: [Edu-sig] RE: Concentric hierarchy / hypertoon (was pygame etc.) > Arthur: > > The tragedy I see is that it is in fact the technologists - > specifically> those immersed in IT - who are emerging as the most > formidable obstacle to > > progress, as I would define it. > > More polemics it'd be interesting to use for new threads. But > maybe not on > edu-sig. The problem though, in my view, is that it is on fourms like edu-sig ( and debian edu list) that the exploration of these kinds of "polemics" are both most relevant and least welcome. Which says something in-and-of-itself. The Free Software movement being a particular kind of "threat", in that the tendency to provoke overconsumption is only enhanced by an offering that is free. Though - (god I hope I got this right) - the folks leading the debian education distribution effort did somewhat belatedly reveal that they are working from a business model based on support of the distribution in school systems. > > More some other time I hope. Starting now ;) Art

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