Mailman 3 October 2016 - Edu-sig

a short essay about programming
by kirby urner Dec. 8, 2022

Dec. 8, 2022

A common "error" (not too serious) that I see in beginning Python (and no doubt other languages, but Python is the one I'm teaching), is having a while condition that appears to put a lid on things, but then the flow all leaks away through break statements, such that the "front door" condition is never revisited. while guess != secret: guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") break else: print("Nope, try again...") What's messed up about the above code is you never really go back to the top in the case where you'd get to leave. Rather, you exit by the back door, through break. So in that case, wouldn't have been simpler and more elegant, even more "correct" (dare I say it) to have gone: while True: # no ifs ands or buts guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") break else: print("Nope, try again...") I see lots of heads nodding, and that could be the end of the matter, but then a next question arises: wouldn't this also be a more correct solution?: while guess != secret: guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") continue # instead of break else: print("Nope, try again...") We're back to having a variable while condition, not a boolean constant, but this time we actually exit by means of it, thanks to continue or... while guess != secret: guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") else: print("Nope, try again...") ... thanks to no continue. This last one is getting a thumbs up, but then I'd pause here and say "continue" can be easier on the eyes. It's unambiguous where it takes you, in contrast to having to scan on down the gauntlet, looking for possibly other open doors. "What happens next" should not require scanning ahead too far. Help us not to get lost. Be a civic-minded coder. I'm thinking of a programming style that advises two things: (a) if you use a while condition that's variable, that's expected to change, then your goal should be to always exit because of that, i.e. that should be your only exit point. Even if some other criterion suggests exiting, you have the option to flip that "lid" at the top, to crack that front door, and bounce the ball out. (b) which is why 'continue' is your friend. You are showing the user where your 'break' statements are, except you don't use "break" statements, as you've given a non-constant condition, and your aim is to make that your ONLY exit point. In short: never use break to exit a while loop unless your condition is while True. Instead, always flip the condition and exit through the font door. However, as soon as I make that rule I can think of good reasons to break it. The other programmers in the room are shaking their heads. Won't we lose information, needed elsewhere in the program, if we "artificially" force a True condition to False. Aren't we, in effect, lying? That concern could be addressed. Keep all the info true, just treat the "lid condition" (it "keeps a lid on it") as a flag. Go ahead and remember the user's guess. allowed = 5 tries = 1 exit = False while not exit: # no other way out guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") exit = True # instead of break continue print("Nope, try again...") tries += 1 if tries == allowed: print("You've maxed out") exit = True continue I think we all understand the main issue: writing reader-friendly code, and rules for doing so. There's something comforting about approaching a while loop and knowing its not a leaky sieve, riddled with back doors, maybe even an exit( ) time bomb. But in the recursion world we want a minimum of two exits usually: when another round is called for versus when we've "hit bottom". Can we have it both ways? Conclusions: Lets not be too hasty with rules of thumb and: Lets keep the reader in mind when writing code. Just because the interpreter knows to compute the flow unambiguously, doesn't mean all ways of writing it are equally reader-friendly. What may seem a gratuitous gesture, an unnecessary flourish, may actually promote reader comprehension of your code, and that should be a goal as much as satisfying the interpreter. Kirby

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MineCraft with Python
by Jurgis Pralgauskis Dec. 4, 2022

Dec. 4, 2022

Hi, intro: many kids like MineCraft :) probably you know/heared of MineCraft Pi https://www.raspberrypi.org/learning/getting-started-with-minecraft-pi/ But there seems to be Py for real MC http://coderdojotc.readthedocs.io/projects/python-minecraft/en/latest/ http://www.instructables.com/id/Python-coding-for-Minecraft/ PS.: a nice article (from js4MC world) https://github.com/walterhiggins/ScriptCraft/blob/master/docs/YoungPersonsG… -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

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turtle coordinates: Y increase downards - as in most graphics API?
by Jurgis Pralgauskis July 2, 2018

July 2, 2018

Hi, usually in computer graphics Y is counted to increase downwards. I casn do it with: setworldcoordinates(0, 400, 600, 0) but then, "right(..)" turns to the left :/ I could swap: right, left = left, right but on errror I get a bit misleading message >>> right() Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> right() TypeError: left() takes exactly 1 argument (0 given) I thought to make this hack for kids, so better clearer error msgs... Any Ideas? Thanks :) -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

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teaching on a 3D canvas
by kirby urner Oct. 31, 2016

Oct. 31, 2016

FYI, here's a posting to a closed archive physics list about using 3D vista generators in general. To teach physics or whatever. The Khan Academy genre is mostly flat chalkboard like surface for all teaching + voice. However as Youtube well demonstrates, there's a trend in the direction of using 3D animations in addition. ==== From: kirby urner <kirby.urner(a)gmail.com> Date: Sat, Oct 29, 2016 at 2:14 PM Subject: beyond the chalkboard: 3D game engines as a platform for physics teaching animations To: The Physics Learning Research List <PHYSLRNR-LIST(a)listserv.buffalo.edu> A segue off the Vpython thread... Studies in Human Motion included as a CDROM in the AAPT conferee packet one year a few back, had raw data for such Youtubes as these, developed using Python + POV-ray (not VPython): https://youtu.be/-j4ZealS1zI https://youtu.be/A0l3Q4Fu20E Body sensors knowing their own position in XYZ space fed time sliced data to spreadsheets, for conversion to still frames then animations. Lots of Youtubes summarize this process of motion capture. I like to think the "contrail" feature, added to Vpython, might have been somewhat inspired by such studies, though I have no evidence that that's true. However, regardless of tool chest, I see a cutting edge in Physics pedagogy is harnessing "game engines" or "virtual worlds" for didactic purposes. Here's a stash of such physics cartoons I stumbled across just this morning, perhaps old news to many subscribers here? https://www.youtube.com/watch?v=9Tm2c6NJH4Y (Physics videos by Eugene Khutoryansky) I don't actually know what this guy's workflow is, the details of his tool chest. I've been poking around on the web looking for more information and may contact him directly. He has collaborators, we know that much. We need to tease apart the adequacy of the physics and/or mathematical content, from the modality and/or aesthetic dimension in which Eugene operates. The output looks kind of computer game like, suggesting an engine (which one?), with a lot of attention to texturing and background. Compare Eugene's style with this other one: https://youtu.be/7u_UQG1La1o Is the surreality of Eugene's world extraneous? A cat watches the action in the Quantum Mechanics video, while the Maxwell's Equations one is inhabited by two angels in a somewhat Gothic setting. Given "Maxwell's Demon" is already in the literature, and that we've all heard of Schrodinger's Cat, I didn't see the imagery as entirely extraneous. He's alluding to known memes. In the mnemonic arts since Cicero and earlier, the idea of using exaggerated-because-more-memorable imagery has been encouraged. I wonder what research and academic papers have been published to draw attention to this emerging genre and to tackle such questions as (A) the efficacy of such animations and (B) given their potential efficacy for some learning styles (witness all the appreciative comments) how to best integrate them into existing curricula e.g. (i) should students just watch them or (ii) also make them? I'm seeing what we might call "Kahn Academy to the next level" i.e. we're moving to a more explicitly spatial / volumetric teaching environment whereas Khan's presentations specializes in 2D planar sketches, are much closer to a chalk board in that sense. I'm sure there's already considerable research on these topics, but as the technology is somewhat new, there's no doubt plenty of room for more. Kirby On Fri, Oct 28, 2016 at 7:11 PM, kirby urner <kirby.urner(a)gmail.com> wrote: > > Probably old news to many here, but I'm just discovering > I'm able to use Vpython aka "visual Python" inside > Jupyter Notebooks with not too much fuss. > On Mon, Oct 31, 2016 at 7:33 AM, Peter Farrell <funcalculus(a)gmail.com> wrote: > Kirby, > > That's great info. I love VPython! Glad teachers will be learning how to > use it. > > Peter > >

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Re: [Edu-sig] Edu-sig Digest, Vol 159, Issue 13
by Peter Farrell Oct. 31, 2016

Oct. 31, 2016

Kirby, That's great info. I love VPython! Glad teachers will be learning how to use it. Peter On Sat, Oct 29, 2016 at 9:00 AM, <edu-sig-request(a)python.org> wrote: > Send Edu-sig mailing list submissions to > edu-sig(a)python.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.python.org/mailman/listinfo/edu-sig > or, via email, send a message with subject or body 'help' to > edu-sig-request(a)python.org > > You can reach the person managing the list at > edu-sig-owner(a)python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Edu-sig digest..." > > > Today's Topics: > > 1. Vpython inside Jupyter Notebooks (kirby urner) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 28 Oct 2016 09:42:59 -0700 > From: kirby urner <kirby.urner(a)gmail.com> > To: edu-sig(a)python.org > Subject: [Edu-sig] Vpython inside Jupyter Notebooks > Message-ID: > <CAPJgG3QcHouzf1uEf9BEx=nz=0iwbBHudHLnj_fpF7uw1T=LQA@ > mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Somehow I didn't expect using Python 3.5 with Vpython in Jupyter Notebooks > would so easy. > > Bruce Sherwood has many examples at his Github account. I uploaded one > yesterday to mine. > > https://github.com/4dsolutions/Python5/blob/master/Shapes%20with% > 20Vpython.ipynb > > Bruce has a viewing solution akin to nbviewer that actually renders the > scene over the web somehow. I embed a JPEG where the rendering goes if > running locally with Vpython installed. > > I wonder who else uses this edtech. I plan to demo it to teachers during an > Hour of Code event come December. > > Kirby >

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Vpython inside Jupyter Notebooks
by kirby urner Oct. 28, 2016

Oct. 28, 2016

Somehow I didn't expect using Python 3.5 with Vpython in Jupyter Notebooks would so easy. Bruce Sherwood has many examples at his Github account. I uploaded one yesterday to mine. https://github.com/4dsolutions/Python5/blob/master/Shapes%20with%20Vpython.… Bruce has a viewing solution akin to nbviewer that actually renders the scene over the web somehow. I embed a JPEG where the rendering goes if running locally with Vpython installed. I wonder who else uses this edtech. I plan to demo it to teachers during an Hour of Code event come December. Kirby

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new JN on RSA etc.
by kirby urner Oct. 23, 2016

Oct. 23, 2016

https://github.com/4dsolutions/Python5/blob/master/Silicon%20Forest%20Math%… Per tweets (@4DsolutionsPDX) I'm advocating Oregon high school (Silicon Forest) computer math (the subject) include Vector, Polyhedron and Permutation types, as a starting place. Python is not assumed but is a reference language for some of us Silicon Foresters [0]. I've long had all the necessary demo software at cp4e.html and other places, but then the Vaults of Parnassus are vast (speaking figuratively, not about any specific cheese shop) so in terms of demos, we're not short on supplies. My suggestion is not that people use my Python code directly (though I make it available), but see these as the types of object anyone might build just to see how they tick. Then swap them around and use many versions, what open free software is all about. This Jupyter Notebook [1], hacked out yesterday, prototypes some of the lambda calc track I sketch out in my video [2] i.e. we'll be traversing a different patch than the calculus continuous math vista. This is a whole new way to earn math credit. Teachers will find it inspiring to be able to innovate in a space largely open for green field development, though we'll pull from the college-level literature. 'Mathematics for the Digital Age' traverses this new territory, as do the pages on crypto at my teaching website.[3] The Vector, Polyhedron and Permutation are each "hour of code" type types, meaning we get through the essentials in an hour or less and then turn to using them as instances in our applications. Kirby [0] https://medium.com/@kirbyurner/notes-from-a-silicon-forester-76d66d2f8742 (Notes from a Silicon Forester: more regional and autobiographical) [1] https://goo.gl/f6xFik (a shortened version of the above or role your own -- also consider using nbviewer option vs. direct to github, though for this particular notebook the differences currently won't matter. [2] https://youtu.be/eTDH7m4vEiM (118 views as of this morning, mostly aimed at high school math teachers in Oregon, whom I'm reaching in greater numbers thanks to Measure 97 (whether voted up or down, the organizing is re-making the state on many levels). [3] over 15 years old by now: http://www.4dsolutions.net/ocn/clubhouse.html

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Re: [Edu-sig] a Circle type with radius, area both properties (fixed)
by kirby urner Oct. 21, 2016

Oct. 21, 2016

> > @area.setter > def area(self, value): > self._area = value > self._radius = self.area / (2 * math.pi) > > Uh oh... I'm in the middle of teaching Session 10 and couldn't figure out why my radius for a smaller area was bigger. Couldn't be. I did my algebra wrong, duh. Here's the debugged version: # -*- coding: utf-8 -*- """ Created on Thu Oct 20 15:43:14 2016 @author: Kirby Urner toggle the import model_property on and off to see the example works the same either way. model_property contains a pure Python emulator of the built in property type. Related reading: https://mail.python.org/pipermail/edu-sig/2016-October/011548.html """ from model_property import Property as property import math class Circle: """setting either the radius or area attribute sets the other as a dependent value. Initialized with radius only, unit circle by default. """ def __init__(self, radius = 1): self.radius = radius @property def area(self): return self._area @property def radius(self): return self._radius @area.setter def area(self, value): self._area = value self._radius = math.sqrt(self._area / math.pi) #duh @radius.setter def radius(self, value): self._radius = value self._area = math.pi * (self._radius ** 2) def __repr__(self): return "Circle(radius = {})".format(self.radius) the_circle = Circle(5) print("the_circle:", the_circle) print("Area: ", the_circle.area) the_circle.area = 50 print("Radius when Area=50:", the_circle.radius)

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K–12 Computer Science Framework -- k12cs.org
by Wes Turner Oct. 20, 2016

Oct. 20, 2016

There is a new K–12 Computer Science Framework: - Homepage: https://k12cs.org - HTML: https://k12cs.org/navigating-the-practices/ - PDF: https://k12cs.org/wp-content/uploads/2016/09/K%E2%80%9312-Co mputer-Science-Framework.pdf - There are: Concepts and Practices - The site provides navigation by: Grade-Band, Concept, Progression - A number of CS organizations and companies have contributed Ideas / Feedback: - It may be helpful (and efficient) to coordinate [Python] CS educational resources with this new K-12 Computer Science Framework: - Additionally, I can't help but wonder whether it makes sense it start with TDD (Test-Driven Development) first when teaching Python (and STEM, and CS, in general).

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a Circle type with radius, area both properties
by kirby urner Oct. 19, 2016

Oct. 19, 2016

Speaking of sharing Python with math teachers, not just librarians (the bravest I sometimes thing), I included this Circle in the session last night (adults learning, andragogy at work): class Circle: """setting either the radius or area attribute sets the other as a dependent value. Initialized with radius only, unit circle by default. """ def __init__(self, radius = 1): self.radius = radius @property def area(self): return self._area @property def radius(self): return self._radius @area.setter def area(self, value): self._area = value self._radius = self.area / (2 * math.pi) @radius.setter def radius(self, value): self._radius = value self._area = math.pi * (self.radius ** 2) def __repr__(self): return "Circle(radius = {})".format(self.radius) the_circle = Circle(5)print("the_circle:", the_circle)print("Area: ", the_circle.area)the_circle.area = 50print("Radius when Area=50:", the_circle.radius) That's right, the area changes if you set the radius attribute and the other way around. I'm not claiming to be the first to think of doing this. We're free to program a lot of geometric types like that, that keep track of their own area and volume (a theme at thekirbster.pythonanywhere.com as well, the tiny Flask application I use as a classroom demo). Here's the Jupyter Notebook I put together before class, where the above Circle type appears: https://github.com/4dsolutions/Python5/blob/master/Descriptors%20and%20Prop… (also viewable in nbviewer.jupyter.org, just paste in the URL). Kirby

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